The scheme involves creating offices with underground parking. Bars and a health and fitness centre will be built along with new housing. Guinness's brewing arm will also get a new headquarters building as part of the plan.
Guinness has teamed up with London and Regional Properties to renovate the 60-acre site.
The proposals also envisage a new underground and bus interchange station to link the existing Piccadilly and Central lines and local buses, while a new road access off the A40 is also planned. Construction work is expected to start in early 1999, with completion scheduled for 2006.
Guinness first opened the Park Royal brewery in 1936 to work alongside its main site in Dublin.
The move is the latest chapter in the transformation of Guinness under Tony Greener, its chairman. Mr Greener recently orchestrated a merger with Grand Metropolitan to create Diageo, the biggest drinks group in the world.
Mr Greener and John McGrath, his counterpart at Grand Metropolitan, have recently embarked on the process of restructuring the combined group's spirits division, a process which is likely to take at least six months and lead to more than 2,000 job losses around the world.
In a separate move, Guinness divulged plans for a new marketing strategy in an attempt to woo younger drinkers to its famous black beer.
The company, which enjoys an 83 per cent share of the UK stout market, is looking to expand the market by targeting 20 to 25-year-olds via music festivals, comedy clubs and sporting events such as surfing.
Sponsorship deals Guinness has entered into include the Fleadh festival of Irish music in London and a chain of comedy clubs called Jongleurs.
"Our core drinker is aged 25-35, but we are quite weak in the 20 to 25- year-old age group," said Jeremy Probert, brand publicity manager for Guinness. "One way of hitting those people is through music, comedy and sport."