Using the method of Census X12 seasonal adjustment and H-P filter,the source of vegetable price fluctuation is decomposed into four components,namely trend factor,seasonal factor,cyclical factor and irregular component.Based on bootstrap granger causality test and VAR model,this paper examines the relationship between the above components and inflation in China.The result shows that,vegetable price fluctuation mainly impacts on CPI through seasonal factor and irregular component.Furthermore,seasonal factor impacts on CPI with seasonal periodicity.The impact of irregular component on CPI is the most significant at early stage,but then decreases gradually.The policy implication is that in order to control the rise of CPI,it is important to reduce inflation expectation,promote cross-regional circulation,reduce logistics cost and improve natural disaster management system.