A strong heavy rainfall occurred in Xinjiang Tainchi during 22~23 June 2010,accumulated precipitation of 6 hours was up to 124 mm. The above-mentioned case has been analyzed using WRF model. The impacts of Tianshan Mountains on the severe convection are discussed. The results show that the low-level northwest airflows of northern Xinjiang were blocked by the topography of the Bogda, and a portion of the winds at a speed of 12 m.s?1 climbed along the windward slope, another part of the air flow around the west side along the mountain climb, and because of the funneling, west air velocity was up to 18~24 m.s?1. The two flows provided dynamic conditions. Because of the terrain blocks and the narrow tube effect, low-levels horizontal airflow velocity decreased with height on the Bogda Mountains of the western slope, causing the hillside to further enhance the level of convergence, relative positive vorticity reached as high as 136×10?5 s?1 which was in favour of precipitation. High and low wind field configuration contrary and vertical wind shear strengthened was conducive to strong convection occurs. Multi-cell merge with local convective cells is the main reason of the occurrence of rainstorm.