Abstract: For the traditional trajectory similarity calculation process based on Euclidean distance function, the trajectory is required to be equal in length and corresponding in time points, however, does not consider the shape of the trajectory, which affects the effect of trajectory privacy protection and the utilization of data to a certain extent. A research on trajectory privacy protection method based on Fréchet distance function was conducted. In this method, trajectories with similar motion directions and similar average velocities were anonymous together, and the Fréchet distance method was used to calculate the distance between trajectories. Finally, the weights between trajectory maps were used to realize the anonymous set of trajectories. Compared with other privacy protection algorithms, there are some improvements in privacy protection and information loss rate, which indicates that this method is effective in processing privacy protection data.