Abstract: The species components,species diversities and soil properties in gap and under canopy in broad-leaved Pinus koriensis forests in Changbai Mountains were studied.The results of the study indicated that the species components and species diversities in gap were different from those under canopy.The Shannon-Wiener index,evenness index and abundance index in gap were higher than those under canopy in seedling layer,while the community dominance in seedling layer increaseed in closed canopy.The physico-chemical properties of soil and litter changed with space and resources usefulness in gaps.The thickness,stock and water holding capacity of litter layer under canopy were significantly(P<0.01) higher than those in gap.The content of total nitrogen and total potassium of litter in gap were 10.47% and 20.73% higher than those under canopy,but the content of total phosphorus and organic carbon under canopy were 15.23% and 12.66% more than those in gap.The water content of 0～10 cm and 10～20 cm of soil layer in gap were 17.65% and 16.17% more than those under canopy,the soil bulk density of 0～10 cm was slightly higher under canopy than that in gap,but there was no apparent difference in the soil bulk density of 10～20 cm.The soil pH were 5.80 and 5.85 in gap and under canopy respectively,and it wasn't significantly different.The content of soil organic matter,total nitrogen and total potassium in gap were 12.85%,7.67% and 2.38% higher than those under canopy.The content of NH_3-N,available phosphorus,available potassium and total phosphorus in soil under canopy were 13.33%,20.04%,16.52% and 4.30% higher than those in gap.