The soil particle size distribution and soil nutrients contents in the soil depth of 0-20 cm, 20-40 cm and 40-60 cm were analyzed, the soil sampling got from ten semi-natural forest plots in forest farms of Wangqing Forestry Bureau, Jilin Province. In addition, the soil erodibility K-value in this region was investigated with the formula calculation method of EPIC(erosion productivity impact calculator) and its affecting factors, the correlation between K-value and soil nutrients were discussed. The results indicated that the mean K-value was 0.060 7 t·hm²·h/(MJ·mm·hm²). The K-value at the soil depth of 0-20 cm was higher than that at 20-60 cm. Higher K-values were found in coniferous and broad-leaved mixed forest than broad-leaved mixed forest. The K-value decreased with increasing stand density and canopy density when stand density was less than 1 200 hm² and canopy density less than 0.75. The correlations between K-value and soil nutrients were in a descending order of total nitrogen, readily available potassium, available phosphorus and total phosphorus in the study area. All soil nutrients were negatively correlated with K-value except total nitrogen. The optimal stand density was about 750~1 200 trees/hm² with higher soil nutrient concentrations and soil anti-erodibility.