To solve the problem of location inaccuracy caused by outliers in azimuth and elevation in single-observer airborne 3D passive locating,a robust recursive least squares (RRLS) algorithm was proposed.On the basis of least square solution,the robust estimation of target location was obtained according to M-estimation principle.In order to ensure real-time locating,the robust recursive least squares algorithm was deduced,and the IGGⅢ weight function was selected as equivalent weight function.Theoretical analysis indicated that the RRLS algorithm can identify outliers effectively,and reduce the influence of abnormal measurement data on locating result by decreasing the weights of them.Simulations show that when outliers exist in azimuth and elevating,RRLS algorithm has the good ability to resist the outliers,ensure the validity of the positioning result and fast convergence.