The `Green Hornet` actress will pick up the prize at Ceasers Palace in Las Vegas on March 30 and CinemaCon chief Mitch Neuhauser claimed she was an "unparalleled" screen star.
He said in a statement: "Since making her debut on the big screen in `The Mask`, CameronDiaz has continued to capture the attention of audiences around the world with her inescapable charm, innate comedic timing, and unparalleled screen presence.
"From the outrageously comedic `There`s Something About Mary`, to the action packed `Charlie`s Angels`, and the critically acclaimed `Being John Malkovich`, Diaz has proven to audiences that she can take on any role and we are thrilled to be able to present such a remarkable actress with the CinemaCon FemaleStar of the Year Award."
Other stars to receive awards at the event include Dame Helen Mirren for Career Achievement and Russell Brand for Comedy Star of the Year.
CinemaCon - which brings together all the world-s major movie theatre chains - runs from March 28 to 31, and features exclusive debuts of new films as well as premiere screenings and star appearances.