The Forestry Tractor Serial Types (FTST) are the technical blueprint for the development of forestry tractors. In order to meet the needs of our forestry, it is necessary to work out China’s FTST for the near future. On the basis of tremendous survey and proper comparison and analysis of the data on the design, manufacture and application of forestry tractois, both at home and abroad, FTST which is suited to the actual situation in China has been drawn up. In this paper, discussions are also made about the principles in determining the types, the grade indexes and the power grades of forestry tractors, in selecting the main parameters and in other problems. The authors consider this FTST to be a well coordinated one with advanced technical and economic indexes, which can meet the needs of different forestry work and of the mechanization of timber production with the least tractor types.