Abstract: Based on the synthetical analysis method,12 times the Bengal Bay storms aroused by 19 times rainstorm cross the whole province in Yunnan have been studied,and some interesting results of rain and circulation characteristic influenced by the Bengal Bay storm have been gotten in low-latitude plateau.Usually,when a rainstorm weather process occur in low-latitude plateau,the storm center locates on the middle,the east and the north of the Bay of Bengal,at the same time,the subtropical high ridge line moves to 15～20°N and west ridge point moves to the South China Peninsula from the South China Sea and the low-latitude plateau is controlled by southwest airstream coming from the front of trough and the periphery of subtropical high.The southwest low-level jet stream from the east side of the Bengal Bay storm have great effect on a heavy rain.One side,the southwest low-level jet stream is playing the transportation water vapor and the energy role.Another side,the southwest low-level jet stream is helpful to keep essential dynamical condition.By analyzing the satellite cloud chart,it is found that mesoscale convection cloud cluster will grow and move into low-latitude plateau coming from the Bengal Bay storm cloud series when a storm grows in the Bay of Bengal.