Abstract: Abstract：In today’s petroleum industry, the optimization of raw materials for ethylene production has become very important. In China, alternatives to naphtha as ethylene cracker feedstock have been studied. Some of the secondary processing oil, such as topped oil is a good raw material for producing ethylene because of its good characteristics, and it is now used more often in practice. Some research on reaction kinetics of topped oil was done and a new model for topped oil pyrolysis was presented and used to simulate the topped oil pyrolysis experiment in Lanzhou Petrochemical Research Institute . The simulation results agreed well with experimental data. Our work provides the basis for further study of topped oil pyrolysis model and numerical simulation.