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By using the conventional observation and NCEP reanalysis data， a study is made to discuss the heavy rain took place in the central Fujian Province on 21 May 2008. The results indicate that the heavy rain took place in the area where the convergence of the divergence term and the advection term of the moisture flux divergence disposed well; the stronger vorticity advection at upper levels promoted the ascending movement; the stronger vertically differential thermal advection of pseudoequivalent potential temperature resulted in the development of instability， in favor of the updraft; and the central position and the strength of the lowerlevel horizontal movement frontogenesis were in good agreement with the location and strength 6 hours in future of the heavy rainfall.