In recent years, human motion capture technology has attracted wide attention. In view of the limitations of existing inertial sensors constrained by cables and affected by magnetic field interference, an inertial sensor using ESP module was designed, which can be used for wireless calibration and real-time data storage. Then, a calibration method based on two standing postures was proposed and a convenient human motion capture system was developed. Finally, an experiment was carried out and the experimental results showed that the designed wireless sensor can realize real-time gesture capture while reducing the hardware volume.