USC has played in the 85-year-old facility since it was built in 1923.
Among other details, the agreement calls for the Coliseum Commission to replace all of the seats, upgrade the video and scoreboard on the peristyle end and add a video-scoreboard on the other end of the stadium.
The commission and the university also will try to get a naming rights sponsor for the facility.
USC will pay rent equivalent to 8 percent of gross ticket sales for home games, half of game-day expenses, and 8 percent of revenue from live television broadcast of games when the crowd is less than 70,000.
The university will retain the right of consent over any amateur or professional football teams seeking to use the stadium, where local officials in the past had tried to lure an NFL team. The Coliseum has been without a pro football team since the Raiders left for Oakland in 1995.