Abstract: In order to explore the effect of water retention agent on the moisture content of sandy soil, the reconstruction of laboratory soil column and artificial rainfall simulation test method were applied. The distribution of soil moisture content within 0 -30 cm depth of soil mixed with different dosages of water retention agent was analyzed. The result showed that with the increasing dosage of moisture retaining agent, the soil moisture content rose apparently. When the dosage of water retention agent was 0.2%, it was time-saving and efficient, and the soil moisture contents of three layers (0 -10 cm, 10 -20 cm, 20 - 30 cm) were 45.42%,48.48%,and 46.16%, respectively, which not only met the needs for growth of plants, but was also cost-saving. Our results are helpful for the rational use of water-saving afforestation and water retention agent, and provide a theoretical basis for arid and semiarid areas as well.