Abstract: A PDR positioning trajectory optimization method based on closed difference correction is proposed to address the problem of accumulated errors in the current pedestrian dead reckoning (PDR) positioning process, which leads to significant deviation of the PDR positioning trajectory. This method uses the closed difference of the PDR trajectory to correct the positioning results of each step, thereby optimizing the PDR positioning trajectory and improving positioning accuracy. The experimental results show that the PDR positioning trajectory based on closure error correction is closer to the actual trajectory, and the average positioning error of the corrected PDR is reduced by 0.283 4 m. The cumulative error probability within 1 m is increased by 22% compared to before correction, effectively improving the PDR positioning accuracy and further optimizing the positioning trajectory.