Considering that the instability of RSSI in indoor propagation makes the localization algorithm based on onetoone mapping between RSSI and location (distance) larger error, by the statistical analysis for RSSI, this paper proposes to build the interval mapping database between RSSI and distance in offlinesampling stage, and then to determine the specific location of the anchor point by the weighted Centroid localization algorithm in rough location area divided by anchor point RSSI in onlinemeasuring stage. The performance test results show that the position estimation error of each test point is slightly different and the average deviation is not high. It indicates that to some extent this method improves the position deviation problem due to the signal fluctuations such as multipath effects, NLOS propagation. Also, it proves the feasibility and effectiveness of this method.