As it had a problem of difficulty to precisely extract the mover position information within the full scope for PMLSM sensorless drive system, and linear motor had the characteristics of wide speed variation range, so a new method of the composite algorithm was proposed. The method was based on the extended Kalman filter (EKF) and closedloop observer position estimation algorithm. When the motor was started and in lowspeed, the extended Kalman filter method was used, but when it was in the high speed, a closedloop observer position was used. When the speed in undertake region, the weighted composite method was used with extended Kalman filtering algorithms and closedloop observer to achieve highprecision position estimation in the system of PMLSM from start to a full range of highspeed. Simulation results showed that the method could estimate the location of the motor accurately in full range of speed.