In this paper, the Huygens-Fresnel principle is restudied by means of wavelet analysis firstly, this builds the basis of the theory for wavelet optics. Then the theory of wavelet analysis is used to analyze the filtering in spatial domain and spatial frequency domain. For example, it gives the space variable processing for the filtering with wavelet in spatial domain, the match filtering for the filtering with wavelet in spatial fequency domain and a single slit and a round aperture for the wave-front filtering. The feasibility for treating the problems in optical field with wavelet transform is discussed, and the theoretical frame of wavelet optics is built.