Choose a wavelet to transform the logging curves, which can obtain a series of scale and depth corresponding to wavelet coefficients. From the view of fourier series expansion and spectrum energy, the wavelet coefficients of optimal scale should be the largest proportion of total spectral energy. Based on the theory above, method of average modulus based on wavelet transform is put forwarded. Find the optimal scale factor through wavelet transforming of logging curves, and establish a correspondence between oscillations characteristic of wavelet coefficients curve of the optimal scale factor and sequence stratigraphy boundaries. This method provides a new way to recognize sequence stratigraphy boundaries.