Abstract: The most important thing for establishing the seed garden or seed forest is to get the genetic gains of some favorable characteristics. According to the experiment on filial generation forest at Baimahe forest farm in Yongren county. The selected good stands had the following characteristics:the genetic force of height growth which is an index of the fast growth was 76%, and that of stock growth which is an index of high production was 48%; the genetic gain was 36. 44%, which was much highier than the project objective-supposed to reach 3%. And more over, the selected good stands could be reconstucted in to seed forest. By using the seeds of the selected forest for silviculture, some unfavorable charac-tenstics such as bending trunk or grains in the stands of P. yunnanensis can be modified, and timber output can be increased.