Designed a wearable motion capture system, which uses the MPU9250 nineaxis attitude sensor and STM32F103C8T6 series ARM. The MPU9250 integrated accelerometer, gyroscope and magnetometer, by detecting the information of the nineaxis attitude sensor, to give the corresponding attitude angle. An EKF (extended kalman filter) algorithm aimed at the attitude fusion was proposed to take the data remove noise.The system takes the data to the computer with the help of Bluetooth technology. The design has a small size, dynamic response, realtime monitoring and so on.