The Lea Valley arena will be built if London wins the Games, but critics have voiced concern about its long-term use.
The London Marathon Trust has agreed to contribute £300,000 a year to guarantee the stadium would continue to be used for international athletics, reports the BBC.
Bid chairman Sebastian Coe welcomed the pledge calling it "fantastic" news.
As part of the post-2012 deal, the stadium would be run by a not-for-profit organisation prepared to make the facilities available to the public.
The Olympic stadium must also retain a running track capable of hosting international events.
