Abstract: It is important to reduce thrust fluctuation of PMLSM in order to meet the demand of speed servo of PMLSM which is easy to produce thrust fluctuation.The paper weakened thrust fluctuation from two aspects of structural optimization and control strategy of motor,namely selecting right shape and arrangement mode of the secondary flux could make the wave of the primary back electromotive force to close sine wave,as well as using control strategy to compensate current by calculating harmonic wave of the stator current through the primary back electromotive force,which could weaken thrust ripple,using closed arrangement scheme of thickness hexagon magnet of skewed slot,skewed pole or uniform magnetizing could greatly weaken thrust fluctuation caused by cogging effect,using measures such as multipole structure,increasing length of air gap and reducing excitation magnetic density could reduce thrust fluctuation caused by edge effect.The experiment result showed that the methods can restrain the influence of the thrust fluctuation of PMLSM on servo system effectively,which has higher robustness.