It summarized the basic principle and characteristics of the rotational molding technology. Based on the experiment of the single axis device the processing of rotational molding was studied and predigested. Especially the heat transfer during rotational molding was analysed and a detailed mathematic model was presented. The heating time of mold and the heating time of resin material was resolved. We also brought forward the solution of analysing the function of time, radius and distribution about melting process.