LBS provide users with highly personalised information accessible by means of a variety of mobile devices that are able to locate themselves. Nevertheless, the wide deployment of LBS can jeopardise the privacy of their users, so ensuring user privacy is paramount to the success of those services. This article focuses on finding a new safe and efficient scheme to prevent LBS server or other users in group from receive real user's personal info. In this scheme, we adopt ASGKA protocol to build safe group and design a cycle-like structure to make group member have safe status.