Abstract: In order to analyze the relationship between deep layer moisture infiltration and rainfall in mobile dunes, using YWB-01 deep layer moisture infiltration recorder and soil water dynamics theory, this study explains the rainfall infiltration moisture transfer process in Mu Us Sandy Land mobile dunes, as well as the infiltration recharge characteristics at the soil layer of 150cm deep. The results showed that: the major source of deep layer soil moisture in mobile dunes was rainfall infiltration. The infiltration recharge amount was 141.4 mm for 2010 and 355.8 mm for 2011, counting for 55.1% and 68.2% of the total rainfall amount of that year. The major recharging season of deep layer infiltration lasted from May to November, and the recharge amount during these months counted for 95% of the total annual amount. When the soil moisture condition remained within the field moisture capacity, rainfall's recharging effect on 150 cm deep soil layer was mainly influenced by rainfall amount and density, with a significant positive correlation (P<0.01) between infiltration and rainfall amount. Water usually infiltrated into the 150 cm deep soil layer at 30 to 48 hours after the start of rainfall. The infiltration recharging rate increased rapidly in the first 3 to 5 hours, reaching its maximum at 3 to 8 hours, before decreasing slowly afterwards. The entire infiltration recharging process could last for longer than 96 hours.