Abstract: By using the precipitation data of Shaanxi automatic station and the reanalysis data of NECP/NCAR, the rainstorm weather in Weihe River Basin from August 24 to 25, 2016 was analyzed. The results showed that the rainstorm occurred under strong subtropical anticyclone, the cold air diffusion in middle troposphere, the low level shear line and cold front on the ground were the main weather system of the rainstorm; the western area of the river basin was mainly affected by the energy front and high energy region system, with lightning and heavy rain; the middle-east area was mainly affected by energy front transit, with strong winds and heavy rain; the northeast rapids of the lower troposphere provided the main source of water vapor for this storm, the join of northeast rapids and southerly wind caused strengthening convergence, which made the short-time strong rainfall possible; rainstorm divergence from low to high showed a dual structure of obviously convergence- divergence, which was conducive to the formation and maintenance of mesoscale convective system; heavy rain area vertical velocity showed a rise—sink—rise—sink distribution, the decrease of maximum value and altitude value was beneficial to the development and maintenance of convection, and the convection was gradually weakened when the maximum value and altitude value were in the same level distribution.