Airborne Single Observer Passive Location have the characteristics of mobility and a wide range impaction, while location method based on the rate change of phase difference also has the characteristic of getting the position quickly and having a high precision. Studied the Unscented Kalman Filter (UKF) apply in Airborne Single Observer Passive Location. It gave out the principle of the position method based on the rate change of phase difference. And it introduced the filtering principle and the filtering process of the UKF algorithm. The simulation results show that, UKF algorithm used in Airborne Single Observer Passive Location have an accurately positioning and rapid convergence.