This paper assessed the effects of small artificial rainfall events (2 mm, 4 mm, 8 mm and natural rainfall as control) on the germination and seedling growth of Chenopodium acuminatum in Horqin Sand Land. Analysis showed that artificial rainfall treatment had significant impacts on the germination and seedling growth of Chenopodium acuminatum (P < 0.05).The rainfall threshold in Horqin Sand Land for the germination of Chenopodium acuminatum is 8mm. The plant number of seedlings in 8 mm rainfall treatment,natural rainfall (CK), 4 mm and 2 mm is in a decreasing order, and the plant height and canopy of seedling in different rainfall treatments were in the order: 2 mm(2.23 cm and 7.15 cm²) > CK(2.03 cm and 6.21 cm²) > 4 mm(1.86 cm and 5.01 cm²) > 8 mm(1.48 cm and 4.72 cm²). Aboveground biomass was in the order of 8 mm (45.26 g/m²) > CK (35.49 g/m²) > 4 mm (26.54 g/m²), > 2 mm (15.26 g/m²). Water use efficiency of Chenopodium acuminatum seedling was positively correlated to rainfall of each time and the aboveground biomass was increased with rainfall amount. Total rainfall at last in the experiment was the same, but the aboveground biomass was significantly different. The rainfall amount×rainfall times was a determinant factor of aboveground productivity of Chenopodium acuminatum seedlings. The density and water use efficiency, germination and seedling gowth of Chenopodium acuminatum all positively responsed to small rainfall events in Horqin Sand Land.