For enhancing guidance effect of infrared imaging guided missiles, the image quality of the missile must be enhanced, denoising of Infrared Image is needed. For the phenomenon that traditional method such as image smoothing, median filter and wavelet analysis can't perfectly de noise the image with heavy density noise, a method that combines mathematical morphology with wavelet fusion and simulation was proposed. The result of simulation shows that the effect of the method based on mathematical morphology and wavelet fusion to process noised image will be better than traditional image de noising methods.