A method based on wavelet transformation for single frame infrared image detection was proposed,which simplified the small target detection problem as a band-pass filtering process.The method firstly decomposes image using a wavelet transformation,and discards the background component located the low-frequency of the image.Next,it removes the high frequency noise by the wavelet analysis,and then reconstructs the new image by the denoised three high-frequency components.Finally,the image enhancement technology is used to improve small target grayscale for the further suppressing the interference.The computer simulation results show that the method presented can detect out the small target precisely and efficiently,and it can overcome some interference problems that come from clouds and buildings.