Synoptic and diagnostic analysis have been performed for a heavy rainstorm in June, 6-7, 1986 in Kunming, Yunnan Province, of which is Kunming'S maximum daily precipitation since 1951. The results show that local heavy rainstorm may occur at single point in early summer in Yunnan Province,with its rainfall equals that in midsummer and autumn. The main characters of heavy rainstorm are as following. Dry cold trough at 500hpa moved eastward while double vortexes attracting and rotating moved westward. Weak cold air at surface induced stationary front with strong vertical wind shear,and therefore there existed a direct circulation and a counter circulation. These are different from the regional heavy rain and heavy rainstorm in low latitude plateau area.