The overload capability of permanent magnet synchronous motor (PMSM) was restricted by core saturation and armature reaction. Conventional design of PMSM could not meet the requirements of some high overload applications. The influencing factors of the overload capacity of PMSM were analyzed. The influences of structural parameters such as stator crack ratio, permanent magnet thickness and air gap length were studied. The influence rules of relevant structural parameters on the overload capacity of PMSM were analyzed. A high overload capacity PMSM with rated power of 1 kW was designed. The finite element simulation results showed that this motor could achieve 5.26 times overload capability.