Abstract: The paper aims to investigate the cause of the severe rainstorm caused by typhoon Rainbow in Guangxi in autumn of 2015, resulting in serious loss of the genesis of late rice. Based on the data of regional mesoscale automatic meteorological station, conventional ground station rainfall observation data and NCEP 6-hour objective analysis data (resolution 1 ° × 1 °, vertical direction 26 layers), using the method of synoptic diagnostic analysis, the typhoon Rainbow was comprehensively analyzed. The results showed that: Typhoon Rainbow moved to the northwest along the edge of the 590 dagpm contour under the guidance of the subtropical high, and intensified in the coastal area, and the later circulation and terrain conditions favored typhoon strong precipitation; The first stage of strong rainfall typhoon based on ontology and its asymmetry structure, rainfall concentrated in the east of the typhoon jet convergence region. The second stage of precipitation was based on the interaction of residual vortex and high-altitude trough, ground convergence line, monsoon jet and cold air, and the rainfall concentrated in the east-south convergence region; The results showed that the uplifting effect of the topographic effect on the typhoon Rainbow had a significant effect on the growth of the two torrential rain centers in Daer-shan and Shitang - shan by changing a set of sensitivity experiments designed in the area. Typhoon Rainbow heavy rain caused serious waterlogging in the southeast, was an important reason for serious loss of late rice.