In the present paper，a two-dimensional flow-reaction mathematical model is developed by integrating a deliberate kinetic and coking model with the k-ε turbulence model and heat transfer model that contains the conduction within the laminar layer near the tubular wall. Numerical simulation on a naphtha cracker and an ethane cracker in Yanshan Petrochemical company utilizing the developed flow-reaction model showed that the predicted exit composition is in agreement with the production data. Reasonable distributions of some product yields and engineering parameters are also obtained in the radial and axial directions. This suggests that the established flow-reaction model can be used for performance simulation in commercial tubular reactor of steam crackers.