Image enhancement is an important issue of image processing technique, which is used to improve the visual quality of image. Pointing at the shortcoming of noise over-enhancement of traditional algorithm, a wavelet-based approach for image contrast enhancement is proposed. On the basis of taking full advantage of multiscale wavelet analysis, firstly the algorithm takes a step of wavelet shrinkage and then differently enhances the coefficients at each scale. To achieve a better visual effect, the algorithm takes in account human visual system while enhancing the wavelet coefficients. Experiment of the algorithm demonstrates that the algorithm avoids over-enhancement of noise while enhancing contrast of the image with good visual effect.