In data opening and sharing, a trajectory privacy protection based on sensitive stay area replacement (SSAR) is proposed in order to improve the availability of protected trajectory while maintaining the same security. Firstly, the stay areas are extracted by analyzing the movement characteristics. Secondly, the sensitive stay areas are obtained according to the user-defined sensitive semantic positions. Then, the sensitive areas are constructed according to the user's privacy requirement needs to randomly select the substitution. Finally, part of the sampling positions in the sensitive area are reset. The parameter selection experiment and the comparison experiment with other schemes show that the trajectory similarity is improved by more than 35% in SSAR. That is to say, SSAR can greatly improve the availability of protected trajectory on the basis of ensuring the safety degree.