To the problem of Linear motors temperature rise , and according to the basic theory of heat transfer, the heat conduction model of stator slot was established, the thermal conductivity of stator slot and the convection coefficient between the stator and rotor were determined .Based on this , the simulation model of motor transient temperature field operating at the polymorphism was established by using the finite element analysis software such as MagNet and ThemNet. Then the temperature field of the linear motor that work under the long-trem and periodic duty was calculated. Through the contrast and analysis between the simulation results and experimental data, the rationality of the simulation model and the correctness of calculation method were verified, which has effective help to design, manufacture and apply such kinds of special linear motor.