This paper describes a improved Mexican-hat wavelet transform with an optical 4f correlator. An optically modified Mexican-hat wavelet matched filter is created by the use of computer-generated holography (CGH). Experimental results for 1-D and 2-D wavelet transform are obtained. The experimental results accord with the numerical results of ref.［8］ very well. The main advantage of the proposed method lies in that any types of wavelet matched filters can be fabricated and their 2-D wavelet transform can be realized.