Abstract: The catalytic pyrolysis of FCC gasoline was investigated in a confined fluidized bed reactor with a specially developed catalyst to maximize the production of light olefins. The experimental results show that the reaction temperature is a key factor to the conversion and the total light olefins yield. The yields of total light olefins vary a little with the increase of catalyst-to-oil weight ratio and steam-to-oil weight ratio. As the weight hourly space velocity goes up, the yield of total light olefins decreases slightly. The optimal reaction conditions were determined for the catalytic pyrolysis of FCC gasoline, and the optimal reaction temperature, catalyst-to-oil weight ratio, weight hourly space velocity and steam-to-oil weight ratio are 660℃, 12, 15h^-1 and 0.8, respectively. A reaction extent function of hydrocarbon catalytic pyrolysis was proposed on the basis of the relationship between the operating parameters and the product yields, and a correlation model of the product yields with the reaction extent function was established.  As the value of the reaction extent function increases, the yield of ethylene keeps increasing, while the yields of propylene and total light olefins have their maximum.