Aiming at improving the quality of reconstructed images of digital holography, based on the analysis of the reconstruction light intensity of digital hologram, a method combining light intensity subtraction and median filtering is proposed. The principles of light intensity subtraction and median filtering are described. Light intensity subtraction based on HRON substraction diminishes the zero-order image and background light. The median filter process effectively minimizes the background noise light. From the comparison of quality of experimentally reconstructed images obtained by different methods, it is shown that the proposed method could effectively improve the quality of reconstructed image of digital hologram.