An improved approximate point-in-triangulation test (APIT) localization algorithm which based on weighted hybrid filtering and center of gravity method (HFG-APIT) was proposed. Hybrid filtering is used to filter abrupt signal strength values to make the data output smoothly and stably. Weighted median is then used to improve the accuracy of received signal strength indication (RSSI), the center of gravity method is used for interior point testing to reduce misjudgment and improve localization accuracy. Simulation results show that the hybrid fi...