Abstract: Lumping theory is used for modelling kinetic results with eleven lumped species for the fluid catalytic cracking system. A computer software for the FCC lumped kinetic model (FCCLR) has alsobeen developed. By this software, the kinetic model was verified in two commercial FCC traits and a FCC pilot plant which used residue as part of the feed. The result shows that the kinetic model can Well predict the yields for various charge stocks over a wide range of process condition in FCC units. The kinetic model has been used in Commercial FCC units and the obvious profits which include upgrading light fuals, increasing yields of gasoline and lowering coke formation have been obtained in operation optimization.