Abstract: The soil bulk density, the soil moisture content, the water storage capacity and the infiltration of grassland, Caragana sinica land and Robinia pseudoacacia land on the loess hilly region in west Shanxi Province were analyzed to compare the differences and correlations. The result showed that all the three vegetation types were able to effectively reduce the soil density of the surface layer. In terms of storage capacity, the retention storage capacity of 0-20 cm layer of the three vegetation types were higher, which performed that the C. sinica land (198.80 t·m-3)>R. pseudoacacia land (166.10 t·m-3)>grassland (87.37 t·m-3), and the retention storage capacity of 20-40 cm layer were C. sinica land (127.30 t·m-3)>R. pseudoacacia land (55.60 t·m-3)>grassland (47.30 t·m-3). It showed that the role of water conservation of C. sinica land on loess hilly area was the highest; in terms of soil infiltration, the steady infiltration rate of C. sinica land was the highest, which was 1.80 mm·min-1, followed by R. pseudoacacia land, which was 1.46 mm·min-1, grassland was the lowest; And the average infiltration rate of C. sinica land was also the highest, which was 4.81mm·min-1, and followed by R. pseudoacacia land, which was 4.51 mm·min-1, and the grassland was the lowest. It indicated that C. sinica land was the optimal choice in loess hilly area; the soil density was extreme significantly and negatively correlated with the retention storage capacity, initial infiltration rate, steady infiltration rate, and average infiltration rate, and was extreme significantly and positively correlated with the non-capillary porosity and both the steady infiltration rate and average infiltration rate. The smaller the soil density, the greater the non-capillary porosity, and the stronger the water conservation capacity of soil.