Abstract: Chinese-pine caterpillar (Dendrolimus tabulaeformis Tsai et Liu) was used four testing the developmental threshold and effective accumulated temperature of its different life stages and instars by means of linear regression method, the method of coefficient of minimum variation and the direct optimum method under varying temperature of laboratory conditions. Through computation and data checking, the authors found out that the theoretical number of generation is fundamently in coincidence with that actual number of generation. It was found there was only one generation per year. Among these three methods, the direct optimum method seems to be the most concise and accurate one.