In order to give more details about the asymmetric structure of typhoon after landing, a case study of typhoon Damrey was carried out by using the synoptic and statistical methods. The observation data from conventional and regional automatic weather stations, satellite imageries and NCEP reanalysis data sets were used to study the possible dynamic mechanism and impacts of asymmetric structure on wind field and precipitation. Results show that the asymmetric structure of typhoon Damrey leads to not only different distributions but also different patterns of wind field and precipitation in different quadrants. The upward movement in the east quadrant and the stable sinking in the northwest quadrant contribute to the asymmetric precipitation distribution. At the same time, the low level warm moist conveyer belt and convective instability are the main mechanism of heavy precipitation.