The Russell Group university will be making lower offers to five 'high potential' students from every school in the local area.
Bristol Scholars is the first initiative of its kind in the country and comes at a time when top universities have faced calls to improve social mobility.
It is being launched by MP Justine Greening, Secretary of State for Education, at St Bede's Catholic College in Bristol.
The University is running the scheme in partnership with Bristol Learning City. Learning can transform life chances and reduce inequality – of significance in a city where one in four children lives in poverty.
Professor Hugh Brady, Vice-Chancellor and President of the University of Bristol, said: "We want to recruit the most able students, regardless of their background.
"These are bold measures designed to address a problem that is seen across the education sector. At Bristol, we have spent £18 million on recruiting and supporting students from disadvantaged backgrounds in the last 10 years, and much as we are making good progress, we want to make a step change in opening up our University to students from all backgrounds.
"We're confident that, in time, we will achieve a more diverse student community at the University of Bristol; this will be a change which will benefit everyone, and something we hope other universities will consider replicating."
Every school or college in Bristol which offers post-16 qualifications is able to nominate five students who demonstrate high potential. They will then receive a reduced, guaranteed offer for the course they wish to study.
Eligibility for the scheme will be based on head teachers' assessment of potential and progress, rather than examination results alone.
Priority will be given to students who have overcome educational or domestic disadvantage and meet a range of widening participation criteria such as being the first in their family to attend university, being part of the Free School Meals cohort, living in care or being a young carer.
In addition to a guaranteed offer, the University will offer academic and pastoral support to the scholars, plus financial support for those whose household income is below £25,000. There will be ongoing research to track the success of the scheme, which will in turn influence future admissions policies.
The initiative has been developed with schools and colleges in Bristol, which are all part of the Bristol Learning City partnership. Thirty-nine Year 13 students are taking part in a pilot scheme, ahead of starting their studies at the University in September 2017.
Marvin Rees, Mayor of Bristol, said: "Bristol's Learning City partners share a vision of Bristol as a place where people are proud to learn and where everyone has an opportunity to be successful. In becoming a fairer city we must reach a place where opportunities in life are not defined by your background or economic circumstances.
"The new Bristol Scholars scheme is a positive step in a better direction. I hope it will create fresh opportunities and open doors to some of our more disadvantaged students, helping them to realise their full potential."
Elisabeth Gilpin, head teacher of St Mary Redcliffe and Temple School, said: "I am delighted that the University of Bristol is recognising and supporting the talents of students in our great city. There are so many highly intelligent students in state schools who are achieving excellent results with the good teaching that is available to them."
"It makes sense for Bristol to hold onto this talent and encourage these talented young people to study closer to home, providing the nurture and encouragement that young people need to take that next step and make their dreams a reality. This is a win/win strategy for the students, the University, the schools and our city."
Marbel Chawatama, an 18-year-old A-Level student from St Bede’s Catholic College, has been nominated as a Bristol Scholar and will start a Law degree in September if she gets the required grades. She moved to Bristol from Zimbabwe seven years ago.
Marbel said: "I was honoured to find out I’d been nominated to be a Bristol Scholar. I know a lot of people want to go to the University of Bristol but don't get the opportunity. I felt really blessed.
"I'm looking forward to developing as an adult at university, because it will give me the opportunity to experience life and have more independence."
To tackle social mobility on a national scale, Bristol will also be making greater use of contextual data – meaning the applicants' school will be taken into account when offers are made.
Those attending 'aspiring' state schools or colleges – defined as those in the lowest 40 per cent of schools and colleges in England and Wales based on A-level results and the number of students applying to higher education – will receive offers two grades lower than the standard offer.
Bristol currently makes contextual offers one grade lower, based on previous research which has demonstrated that students who entered the University from lower performing schools with A-Level grades one grade below normal requirements went on to perform at the same level as students admitted from higher performing schools.
Diversifying the student population is a key aim of the University’s new strategy, which was launched last month.
Professor Les Ebdon, Director of Fair Access to Higher Education, said: "I am delighted to see the University of Bristol working in such an innovative way to improve its diversity. With the Bristol Scholars scheme, the University is building on a history of innovation in its fair access work.
"All over the country, universities are working with schools in many ways to find and nurture pupils' potential. But there is still a long way to go before everyone who has the potential to go to university has equal chance to do so, and the Government has set ambitious goals around this. So I would like to see more universities thinking creatively about how they support talented young people."
Arne Carlsen, Director of UNESCO's Institute for Lifelong Learning, said: "Learning Cities take the lead in developing inclusive sustainable growth through a commitment to lifelong learning. This is taking place through our network in the UK and abroad. Today, Bristol and Swansea – tomorrow, more cities of the future."