There is no shape,texture or color information in the observation image of the dim target under the starry background,and it has high similarity with stars and noise.Background suppression and noise elimination is the basis of retaining the target information to the maximum extent.Based on the analysis of the histogram characteristics of the observation image of small and dim target under the starry background,a starry background parameters estimation method is proposed,which continuously discards the high-gray areas and reduces the sample variance,and the background parameters are used to suppress noise.Experiments show that the method can filter out most of the noise,retain and enhance the target to the maximum extent under the influence of complex background noise and stars.