Abstract: Solubility is useful in verifying the validity of geochemical codes which are a part of predictive transport models. ²⁴¹Am or ²⁴³Am is considered one of the most important radionuclides in the high-level waste （HLW） disposal study. The accurate determination of Am solubility can provide valid data for safety assessment of deep geological disposal of HLW. The solubility experiment of Am(Ⅲ) in Gansu Beishan groundwater at three-different temperatures (30, 45 and 60 ℃) were carried out. The effects of temperature, sulfate, carbonate and pH on solubility of Am(Ⅲ) were also investigated in a series of experiments. The results show that the Am(Ⅲ) solubility increases with the concentrations of sulfate and carbonate while the Am(Ⅲ) solubility significantly decreases with the increases of temperature and pH. Although Am(Ⅲ) solubility in the groundwater is greater than that in the distilled water due to complexation of anion in the groundwater, but the Am(Ⅲ) solubility in the groundwater decreases dramatically as a result of increasing temperature and pH due to higher temperature in near field environment of disposal repository and alkalinity of the groundwater, which is advantageous to the disposal safety.