The popularity of WLAN and mobile devices makes the development and widely use of location-aware systems and services possible. Since the Received Signal Strength Indication (RSSI) can be obtained by most mobile devices, the fingerprinting method based on RSSI becomes a simple and efficient method of Indoor Location (IL). This method needs to use the empirical measurements, propagation modeling or their combination to build the fingerprinting map in the offline phase, and the map plays an important role in the location process. The inversion propagation model can predict the propagation loss between any two points along the virtual propagation path from the base-station to the mobile-station, which precision has been presented in. In this paper, the algorithm of Inversion Propagation Model is used to build the fingerprinting map in order to find a new method that can keep a high degree of accuracy as well as simplify the process and improve the efficiency of map building.