Abstract: The paper aims to explore the premature rice crop failure, vegetable seedling rotted root, and the growth retardation of litchi and longan during young spike period caused by the torrential rain in Yulin on May 20, 2016. Based on NCEP 1°×1° global objective analysis data, conventional meteorological data, TBB from FY2E infrared cloud and Doppler radar data, the authors analyzed the heavy rainstorm mesoscale system (MCS) and dynamic mechanism. The results showed that: (1) heavy rainstorm occurred in the“two slots and one ridge”under the large circulation background, the combination of the eastward flow and the warm and humid air flow in the northwest side of the subtropical high pressure provided a favorable circulation background for MCS; (2) the coupling of the high-level strong divergence and the low-level convergence was favorable to the vertical uplift and the occurrence of the MCS; the rainstorm occurred at the right side of the low-level jet entrance; (3) there was a clear convergence of water vapor over Yulin, providing sufficient water vapor, which allowed the MCS to maintain; (4) MCS occurred at the center of the convective cloud, i.e. the area with larger gradient of TBB. The above reasons for Yulin large-scale heavy rain weather led to heavy loss of early rice crop and other heavy agricultural disasters. This article intends to summarize the experience to better grasp the background of similar weather pattern and offer a reference for disaster prevention and mitigation.