As the traceability system has the function of specifying potential liability and other characteristics, it is becoming popular and being adopted by many countries abroad. It will be an effective measure to guarantee vegetable quality and safety in the wholesale markets if we establish this traceability system in China. This paper reports on a study which examined traceability proportion differences when vegetables enter and quit wholesale markets, and then attempted to analyze these differences. Based on the study, the paper conducts a regression analysis of vegetable suppliers' behaviors, and offers some explanations of the regression results. The main conclusions can be stated as follows: First, the implementation proportion of vegetable traceability system is still not high in Zhejiang Province, and the vegetable suppliers are not highly aware of the concept of traceability and its system; Second, vegetable suppliers' behaviors are influenced by many factors which include vegetable acquisition channels, market admission registration, government detection frequency, years of dealing in vegetables, income proportions, relative operation size in the market, and the degree of understanding of the traceability system. Implications of the study are discussed regarding the improvement of the vegetable traceability system in China, which include active promotion of the construction of vegetable production base and cooperatives, and the improvement of the flow of wholesale format.