For the copyright protection and information hiding of digital video，a new video watermarking algorithm based on interframe wavelet transform is proposed. Firstly, video frames are divided into groups with the same frame number, and interframe wavelet transform is performed on each group with maximum levels, which gets several high frequency frames and one low frequency frame. The low frequency frame contains most of the energy of video sequence, while the high frequency frame contains little energy. Then, watermarking is embedded into the low frequency frame in the SVD field. The proposed watermarking embedding and extracting algorithm uses only four frames for performing wavelet decomposition per operation with lower memory demands. The experimental results show that this method has very good imperceptibility and good robustness.