The health human risk of inorganic arsenic (As) in groundwater was assessed usingthe skin cancer, bladder cancer, lung cancer and the union of bladder cancer and lung cancer were selected as the endpoints. The geometric mean (GM) of arsenic concentrations in groundwater across China was estimated to be in the range of 1.597~6.216μg/L. After adjusting area of each province, the GM of As was 2.773μg/L. The average daily dose (ADDs) for maleand female of As via intake of underground water were estimated to be 0.088μg/(kg bw·d) and 0.093μg/(kg bw·d), respectively. Thus, the expected risk for male raised by As via groundwater exposure was calculated to be 1.32×10^-4 for skin cancer, 9.83×10^-4 for bladdercancer, 5.88×10^-4 for lung cancer, and 1.48×10-3for joint cancer risk (bladder cancer and lung cancer). The cancer risk for female was 1.35×10^-4, 9.42×10^-4, 1.49×10^-3, and 2.31×10^-3 for skin, bladder, lung and the joint cancer risk, respectively, higher than those for male. In most provinces, the risk is higher than the acceptable risk level of 10^-4 for As set by US EPA.