With the rapid development of web video application, video similarity search has become a hot research field in content-based video retrieval. Many efforts have been carried out to improve the effectiveness and efficiency of similarity search in large database. In order to solve two challenging problems: similarity measurement and search method, a novel efficient VSS approach is proposed in this paper. A compact video signature was computed based on Spatial-temporal features of video sequences. The video similarity was measured by an efficient computation of the distance of video signature in feature space. For the scalable computing requirement, a new search method via Signature Index Table was presented by index clustering. The experimental results from the query tests in large database show this method is highly efficient for similar video search.