Abstract: During 1991 to 1995,a series of high seed yield tests were conducted in the Slash Pine Orchard in Changle Forest Farm.After knowing the cause for lower seed yield, the density was reduced from 270 to 135 tree/ha.Several clones,such as Ⅱ-33, Ⅵ-60 which could produce more seeds than the others were found.These clones possess the characteristie of earlier flowering.It means their conescould be developed normally in a lower temperature condition.Fertilizing,epecially P,K could increase seed production with a rate over 100%, the Zn and P could double increase the rate of seed from the cone.A slight beat on the hark of tree trunk called "kei-jia" in Chinese could promote flowering and increase cone production over 30.0%.Three years after the treatment,the tree trunk is still normal,it means the slight beat at the bark could be used in the production.It is useful to pollen or spray MG-powder,a special powder for seed production, during flowering period,which could increase the seeds from the cone with a rate of 47.6%,51.2%, respectively.The cone pests should be controlled.Application of all these methods made the rate of the seed out of cone increase from 0.59% to 2.05%, the seed yield increased from lower 3kg/hm2 in 1992 to over 18kg/hm2 in 1995 in the whole orchard with on area of 20hm2.