She was named Indianapolis 500 Rookie of the Year in 2010, and placed 13th last season racing for KV Racing Technology.
The Switzerland-born driver, who left for the United States when she was 18 to drive in the Formula BMW USA series, will join Sauber's preparation programme with the aim of earning a superlicence and preparing for a race seat in 2015.
"This is a major step towards me achieving a life-long dream and I'm so happy to have the opportunity to take this step with such a great team," De Silvestro said in a statement.
"The Sauber F1 Team is a team with a legacy and the only Swiss team in Formula One, which I think makes this even more exciting."
Mexico's Esteban Gutierrez and experienced German Adrian Sutil will drive for Sauber this year and Dutchman Giedo van der Garde is the test and reserve driver.
"After four years in IndyCar, Simona's ambition is to enter Formula one in 2015," team principal Monisha Kaltenborn said.
"We regard her as a very talented race driver, and we, therefore, decided to take her on board as an 'affiliated driver' and support her on her way to the pinnacle of motorsport."
(Reporting By Josh Reich, editing by Ed Osmond)
