Abstract: This paper based on date of the filial generation of masson pine Jianyang district determined by the Yangkou Forestry Centre, Fujian province in 1986, the gradation famities adopted the relative index on timber volume per mu of family and rationally analysis to the gradation of famities, and them applied Fuzzy ISODATA cluster selecting grading factors. The paper also provided quantitative basis of qualitative criterion for drawing up and discriminating families.