Abstract: The algorithm of EKF suitable for multiple passive sensors is presented.Thinking about the problem of nonlinear measurements in target tracking with multiple passive sensors,the unscented transform based unscented Kalman filter suitable for nonlinear systems is applied to the target tracking with multiple passive sensors.Detection fusion solution is adopted and the bearings measurements from multiple passive sensors are formed into one vector,then the algorithm of UKF suitable for multiple passive sensors is presented.Comparison of two algorithms in passive tracking to a 3D target with multiple passive sensors is illustrated that the tracking precision of UKF-based is higher than that of the traditional EKF-based.