To solve the problem of low precision in traditional RSSI location estimation schemes in WSN，the virtual anchor RSSI（VA-RSSI）localization algorithm with RSSI valid threshold was presented. The proposed algorithm has three improvements，including update of virtual anchor nodes，the conception and formulation of confidence levels of virtual anchor node，and coordinate calculation of blind nodes by using weighted least square estimates. Simulation results demonstrated that the VA-RSSI algorithm reduces the distance estimation error effectively and achieves better precision at the same network environment.
