Abstract: The development of commercial unit simulation calculation software of heavy oil catalytic cracking was studied, including the building of 11 lumping heavy oil reaction network, model deduction of different type reactors, setting and calculation of unit factors. The gas products correlation model strengthened the software function and met the requirement of predicting gas distribution; The feed structure correlation model reduced the work and difficulty of analysis, and strengthened the software adaptability. The simulation calculation of FCC aromatic extraction combination technology and the validation results show the strong adaptability and high accuracy of the software.