Abstract: Fluctuation of vegetable price is not only the focus of the public, but also the basis for farmers’ arranging production. The studies on the fluctuation law have practical significance. By using Census X-12 method and H-P filtering method, this paper analyzes the fluctuation law of 8 vegetable wholesale prices in Tianjin from 2007 to 2013. The results show that, under the influence of the production, circulation, season, climate and multiple factors, the overall price of vegetables changes in rising trend, seasonally fluctuated obviously and are affected remarkably by natural disasters and other unexpected factors, vegetable prices were recurring cycle features of "two years rise and a year falls" . According to the results of seasonal adjustment, we make model to forecast 2014 vegetable prices trend in the paper, and the prediction results are in good agreement with the actual.