In order to overcome defects in existing ASCTS (Agricultural Supply Chain Traceability System, a new traceability system based on Multi-Agent System (MAS) is put forward. By qualitative method, I analyze problems of application of Agent technology in tracing quality of agricultural products. Physical model is built for this system and structure of traceability system is determined. Finally, algorithm is presented for major entities. From analysis of algorithm, it is proved that this system has some reference value in improving breadth and depth of product traceability.