In　order　to　effectively　improve　the　imaging　quality　of　the　nighttime　image,　An　improved　wavelet　threshold　denoising　algorithms　which　could　make　up　the　shortage　of　soft　and　hard　threshold　function　was　researched　in　this　paper.　The　denoising　effect　is　much　better　when　the　parameter　e　is　adjusted　to　a　certain　value.　The　simulation　result　shows　that　the　gaussian　noise　in　the　night　image　is　removed　effectively.　The　Pseudo-Gibbs,　Ringing　effects,　the　lack　of　details　and　edge　blur　were　overcome　obviously.