For infrared image with low contrast and low signal-to-noise ratio,an infrared image enhancement method based on pseudo median filter and wavelet transformation is presented.Firstly,pseudo median filter is used for de-noising,then the wavelet transformation is adopted to decompose the image.To prevent the small target to be filtered as noise,the coefficient below threshold is filted by algorithm based on neighbor coefficient keeping.The coefficient above threshold is enhanced by nolinear method.Finally,the inverse wavelet transform is applied to synthesis image which can obtain the enhanced image.A group of experiment results show that the presented algorithm reduces the noise and improves the image contrast.The result image fits visual sense characteristic.