Abstract: This is an experimental research on the TRMM(3B42) data variational correction for a total of 184 days of precipitation in the 25 Bengal storm rainfall process during 1998—2010.The results show thatfirstly,the generalized error field of TRMM data which were based on variational correction method is uniform convergence.The number of iterations will be no more than 800 times when precision is equal or less than 0.001 mm,regardless of the approximate value being large or small.Secondly,the corrected TRMM field which embodied the synoptic scale information and was obtained by the ground observation network well described the discrete features of precipitation,especially for the regions lacking precipitation observation.In this case,TRMM data is of great help.Thirdly,considering the average RMSE of the original TRMM data and the corrected TRMM data against one hundred observations which are not involved in variation correction ,the errors of corrected sample are less than those in the un-corrected,and the average error of 184 samples has been reduced from 3.73 mm to 1.51 mm.Evidently,variational correction helps to reduce the errors of TRMM field.