Diagnostic analysis is done on a heavy storm process occurred on July 5th,2012 in Henan province,based on data of NCEP,satellite image,radar echo,sounding and ground observation from regional stations,in order to reveal the characteristics and mechanism of regional heavy storms.The results show that the low level shear line interacts with the ground shear line and the surface mesoscale convergence line to produce the heavy rainstorm,under the influence of trough and subtropical high.Mesoscale characteristics analysis reveals good indicators of this strong precipitation process,including the cold air movement,the deep southwest jet stream of troposphere,the formation and development of mesoscale convergence and shear line.The distribution and intensity of vertical helicity at 700 hPa are in agreement with the rainfall area and center.The research results provide reference for the improvement of regional rainstorm forecast.