Silk fabrics density are usually very high because the silk yarns are finer than spinning yarns, so it difficult to calculate the density quickly by routine methods. According to the characteristics of silk fabric, a method to measure silk fabric density based on multi-scale wavelet decomposition is developed in this study. The wavelet multi-scale analysis is an ideal approach to extract the detail features from the fabric images. And the results showed that this method is superior to normal wavelet decomposition. It is an efficient and accurate way to measure the density of common silk fabrics automatically.