Airborne passive radar is faced with interferences of Doppler broadening direct waves and strong clutters, but the traditional Normalized Least Mean Square (NLMS) algorithm is difficult to eliminate such interferences.In order to solve this problem, a Variable-Step-Size Range-Doppler NLMS (VSS-RDNLMS) algorithm is proposed.The algorithm is improved on the basis of RDNLMS algorithm to eliminate clutters on the distance and Doppler synchronously.At the same time, the output error signal and system noise are used to control the step size.Therefore, the steady-state error of the algorithm is reduced on the premise of ensuring the convergence speed.The simulation results show that, under the same simulation conditions, the VSS-RDNLMS algorithm can obviously improve the clutter cancellation performance for airborne passive radar, effectively reduce the cancellation residual, and improve the SNR of target.