The combination of image features with singular value decomposition algorithm and digital watermarking algorithm based on wavelet transform respectively makes possible the advancement from pixel watermarking to content watermarking, which effectively solves the contradiction between perceptibility and robustness of conventional watermarking algorithm. This paper first gives a review on conventional singular value decomposition algorithm and wavelet-transform-based digital watermarking algorithm, and then makes a thorough analysis of their respective features, advantages as well as the similarities between the two. Improved feature extraction schemes of digital watermark which combine image features with the two algorithms respectively as well as the feature extraction scheme combining the two algorithms are put forward for the comparative analysis of corresponding principles and processing effects. The experimental results indicate that the content-based (instead of pixel-based) watermarking algorithm can better satisfy the perceptibility and robustness of digital watermarking, with huge application potentials and more development space.