Abstract: The weight leakage algorithm is a kind of frequency adaptive algorithm that is suitable for multiple narrow band jammer suppression in direct sequence spread spectrum system. The aim of this paper is to the problem that the weight leakage algorithm did not work well when the power of jammer changed, in order to overcome the shortcoming of constant step size frequency-domain adaptive algorithm. Based on studying the relation between step factor , leak factor of weight leakage adaptive filtering, and the jammer suppression factor , a novel variable step size frequency-domain adaptive filtering arithmetic was proposed through theoretical derivation, the performance and convergence was analyzed in the case of timing variable jammer suppression for the GPS receiver . This arithmetic is superior to constant step arithmetic in environment that power of jammer changes. The computer simulation results confirm the theoretical analysis and show the algorithm performance is better than that of former algorithms.