Numerical simulation on the inner flow, heat transfer, mass transfer and cracking reaction in vortex reactors was carried out with gas-solid two-phase flow-reaction model. The detailed information of flow field, temperature field and concentration field of vortex reactor was obtained.Results showed that the motion of particles was cork screw path. The temperature in vortex reactors had certain rule and temperature gradient in axial and radial direction. The distributions of velocity had relations with different angles of rotor blade and no relations with hot oil temperature. The entrance velocity of vortex reactors was bigger and later flattens.