This paper is to propose a method for depth estimation in a 2D image using wavelet analysis. According to our observations, the high frequency components represent focused objects in images of limited depth of field (DOF) and their high frequency wavelet subbands contain high energy. In our approach, each image is first transformed to YUV domain and the Y component is extracted for further analysis. Afterwards, the high frequency bands are derived with wavelet analysis. Through two stages of smoothing and scale manipulation, the depth map data with less error can be used for some 3D display. The experimental result shows that the proposed approach is effective and efficient for depth map estimation.