The volume holographic correlator (VHC) can perform multi-channel inner products calculation. By encoding the input function and two-dimensional Walsh functions into input image and stored images respectively,a method that using volume holographic correlator to perform two-dimensional discrete Walsh transform (DWT) is proposed. This method has a potential to approach a high processing speed. By use of speckle modulation and interleaving method,the calculation accuracy can be improved. An experiment is carried out,and the correspondency between experimental results and theoretical ones proves the effectiveness of the method.