Infrared imaging process is affected by environmental factors and characteristics of system which inevitably result in an infrared image with low contrast low signal to noise ratio and fuzzy edge.So image enhancement is necessary.Based on the study on image processing we proposed a new method of infrared image enhancement. First a filter method combining median filter with mean filter was used for filtering image.Then the improved OTSU was used to segment the image and plateau histogram equalization was used to enhance the image segmentations. The image edges that need sharpening was determined based on the image segmentations and the enhanced image was obtained by using simple weighted average method.Simulation results show that this method is feasible and has fine enhancement effect.