Abstract: Dewatering is an important measure to ensure the safety of urban rail transit construction. The evaluation and disposal of its impact on the surrounding environment is a very important issue in the current underground construction. Based on the geological characteristics, surrounding environment and engineering experience of Xi’an, the precipitation risk evaluation system and disposal measures of Xi’an metro engineering are proposed. Dewatering risk evaluation system is based on stratigraphic characteristics, groundwater depth and proximity degree, which are three core factors affecting the safety of the surrounding environment. Based on this, risk classification and disposal measures are formulated. In the risk assessment, the characteristics of heavy dewatering deformation of saturated soft loess are emphasized. Based on a large number of engineering practices, this paper not only contributes to the improvement of the Code for Risk Management of Underground Engineering Construction of Urban Rail Trantransit, but also can effectively guide the design and construction of the project, and avoid the surrounding environmental risks caused by subway construction in urban built-up areas.