Abstract: Six unrelated clones of Chinese fir in a seed orchard were mated using full dialel mating pattern with selfing and open-pollination.Seeds were collected from each parent, testings were also established.And then, in this progeny test plantation, the 4-6 flowered trees in one full-sib family and one open-pollinated family were chosen to be mated in involving self-, back-, within sib-and outcrossing.Three groups of experiments indicated that inbreeding resulted in much reduction both in seed germination and seedling height growth.The inbreeding depression has increased with the increase of inbreeding coefficients, Comparing with outcrossing, the percentages of seed germination of selfing, backcrossing and full-sib-mating, half-sib-mating have been reduced by about 88%, 42% and 20%, and those of seedling height growth reduced by about 27%, 17% and 13% respectively.There were significant differences in inbreeding depression between the families or mating parents.