Space-Time Adaptive Processing (STAP) is an effectivemethod to suppress interference in Global Navigation Satellite System (GNSS).But in high-dynamic environment,conventional adaptive anti-jamming algorithms are invalid since jammers may easily move out of the array pattern nulls.To solve this problem,a new null-widen method based on the Laplace distribution model is deduced in this paper,the method can get wider null at direction of jammers.However this method is computationally intensive by using STAP,thus a new null-widen method based on reduced-dimension multistage wiener filters (MWF) is deduced here.It has proved in simulation section that the new method can get better performance in few snapshots.