Soil moisture properties under the pure and mixed plantations of Pinus koraiensis and Frax inus mandshurica were measured and analyzed. The result showed that for each soil layer or the whole soil profile, the soil bulk density under the mixed plantation was lower than that of the pure plantation of Pinus koraiensis. But the total porosity, capillary porosity, non-capillary porosity, soil maximum moisture capacity, capillary capacity, field capacity, wilting point, available water capacity, water storage capacity, permeating coefficient under the mixed plantation were all significantly greater than those of the pure plantation of Pinus koraiensis, with the relative increases averaged over the entire profiles being 19.17%,21.50%,12.17% ,32.68%,24.29%,42.22%,19.72%,27.71%,12.17% and 39.44%, respectively.The results showed that the soil pore condition in the mixed plantation,compared with the pure plantation, was improved, resulting in better functionality of water and soil conservation.