The technology of single observer-passive location formaneuvering emitter in the sky such as battlep lanes, missiles and rockets has significantmartial importance and prospects for app lication.A technology of single observer-passive location formaneuvering emitter is introduced based on existingmethods according to transmission characteris-tic of infrared radiation in the air. And the algorithm of Extened Kalman Filter ( EKF) is applied to the method. With the help of computer simulation, the method is proven to be correct and effective. The method can be applied to the antiaircraft system against covered target and low altitude breakthrough for defence.