To resolve the problem of degaussing of the magnetic pump, a new drive device is designed, consist of external magnetic rotor,isolation units and torque ring. Based on ANSYS12.0 analysis software, electromagnetic coupling method is firstly adopted on the simulation of this drive device. The comparison of simulation value and experimental data indicates that this method is feasible. For the purpose to provide evidence for more in-depth study of high temperature magnetic pump. Especialy,some key factors effecting on torque are considered, and this will provide references for further study of high-temperature magnetic pump.