Abstract: In terms of location privacy protection,much of those exiting methods are only aim at protecting the user’s current location.But in reality,users are always in the state of continuous movement,and may make queries in every location along with their movements,which called moving trajectories.So it is important to protect those trajectorise from being discerned by others in the condition of continuous movement. Aiming to protect the trajectory privacy,this paper proposes a method based on dummies. According to the parameters given by user, the algorithm generates some fake locations and dummies , promotes the strength of protecting the trajectories privacy by reducing the identification probability. Comparing with the method of generating dummies randomly ,the experiment shows that the menthod has the advantages on the time consumption and the numbers of generated dummies.