High concentrations of arsenic (As) in groundwater has led to adverse effects on human health and ecosystem due to the risk of As toxicity from drinking water sources. Diverse mechanisms govern arsenic mobilization in groundwater. In this study, scatter plot, cluster analysis and factor analysis were employed to investigate the occurrence and mechanisms controlling As concentrations in shallow groundwater at Yuncheng Basin, China. The research shows: (1) As contents in shallow groundwater is closely related to human activity. (2) It is favorable for the release of As in aquifer under reducing environment. Our findings suggest that cautions should be made for the management of shallow As contaminated groundwater.