Based on Doppler radar and NCEP/NCAR reanalysis datasets,mesoscale characters of the ocean-effect snowstorm in the north coastland of Shandong Peninsula south of Bohai sea in the December of 2005 is diagnostically analyzed by RAMS4.4.The results show that the snowstorm occurred with the northwest airflow,large sea-air temperature differences and the special hill topography.Long life cycle adverse wind regions in Doppler radial velocity images were observed during the snowstorm.Results of numerical simulation indicate that the RAMS can successfully simulate the location and evolution of the ocean-effect snowstorm in the coastal area.The mesoscale vertical circulation is found when the snowstorm occurs,and the snowfall increases with the strengthening of updrafts and the development of adverse wind regions.