In this paper a new method to inspect the speed and position of linear motor is presented. We find the mathematical model of PMLSM in the rotationary dq coordinate contains the nonlinear term and it satisfies Lipschitz conditions. So we introduce an observer design method for Lipschitz nonlinear systems in the presence of bounded disturbances and give the stability condition of the observer with the form of LMI. Based on this method we estimate the speed of the linear motor, the result of which can be used to calculate the position of motor’s magnetic pole together with formulae. To support the theoretical concepts, we set up a sensorless linear servo control system for PMLSM. The simulation results prove the feasibility of the proposed method.