The management and retrieval of Image/Video database based on their content has became an important search area in recent years. MPEG-7 standard provides a rich set of tools for completely describing multimedia content. In this paper

we explore the issue on content-based video manage and retrieval system. A video database described by MPEG-7 video content description and MPEG-7 semantic description is realized. Within this system

natural language comprehension technique is incorporated which makes it possible for user to query conveniently by more natural language

and synonymy lexicon is used to reduce the redundancy of features. We combine Low-level visual feature and high-level semantic description together

and adopt relevance feedback mechanism which enables user to find his target video step by step. Also we use semiautomatic intelligent weight innovation algorithm

which can make the features more and more reasonable. Experiment result shows that we can manage and retrieval video by content expediently and effectively using this system.