Abstract:Using the surface and air sounding observation data of winter precipitation in Dalian from 2003 to 2012, we obtained the maximum and minimum factors which were used to judge the precipitation types and classified as “MAX class” and “MIN class” to analyse and discuss the precipitation process dynamically. During the process of discussing the factors which affect the precipitation types in winter of Dalian, the method of the mean temperature of layers was used to research the precipitation types. Comparing it with the method before, which use the temperature of single layer or the thickness of layer, we considered the evaluation results of all factors, and found using the factors which belong to the category of mean temperature are better than the factors of other categories. The mean temperature of the conventional isobaric surfaces is easy to compute, suitable for the operation of weather forecasting. In addition, we also designed a “step expel method” and use it to validate the winter precipitation types in Dalian 2013, on the basis of the surface and air sounding data of Dalian, and have obtained ideal results. Then we used the GSM grid data of Japanese mathematical forecast in 2013 to simulate the weather prediction, getting good results.