In order to conduct the integrated management in the whole process of plastics waste management, plastics waste generation should firstly be studied, especially the generation of each kind. The results of factors acting during the generation process should also be studied. Using Beijng as an example city, this paper established a predicting model for the generation and proportion of each shape and component of plastics waste, and analyzed the generation characteristics and trend of plastics waste in Beijing according to the predicting results. In terms of shape, the plastic film has the largest proportion. While in terms of component, PP and PE have the largest proportion among all the components.