Teaching playback is the major way of robot path tracking. Its working principle decide the complex degree of robot working. With the technology of human motion tracking, we can simplified robot teaching program and improve the safety of working environment. This article focus on the human motion tracking based on the technology of MEMS. With the 9axis inertial sensor, which include an accelerometer, a gyroscope and a magnetometer, and the method of complementary data fusion, the data accuracy of hands will improved. The results of linear path motion and space continuous path motion experiment show that the date calculated by this method has the high accuracy, can be used in robot teaching playback.