Abstract:With the increasing of Automatic Weather Stations (AWS) of China Meteorological Administration (CMA), it is very vital for meteorological operation to develop and set up a quality control system of observations from AWS. As a qual ity control flow from observational station to provincial meteorological data de partment, subsequently to national data department, the threestep quality cont rol system in operation for observations from AWS has been studied since 2004. E ach step has automatic control technique and interface application technique, al lowing analyzing and amending some data. The threestep quality control system c ould improve the collection and disposition level of data observed at AWS and cou ld insure the data quality. The operational flow setting in the whole quality co ntrol system, the quality control technique and the quality control information have been presented.