The foreign and domestic technology research and industry application status of permanent magnet synchronous traction system for rail transit field were introduced, involving highspeed train, light rail, subway and so on. The technology advantages, risk analysis and preventive measures of permanent magnet synchronous traction system were demonstrated. The design ideas, key technology and analysis simulation test for prototype design of permanent synchronous traction system were described in detail using CRH5 as prototype. Ground joint test and loading assessment results showed that the system core technologies such as traction control unit, auxiliary control unit and control algorithm were safe and reliable, and the system efficiency was improved by above 3%.