Abstract：Research purposes： The Metro station is always in the city downtown, and lots of factors should be considered carefully. One of the factors is the lateral deformation of the diaphragm wall. The deformation is difficult to investigate by analytic solutions, and the numerical simulation is hard to demonstrate all the mechanisms. Therefore, the spatial  evolutional mechanism and the statistical characteristics need to be explored based on the long-time monitoring data.  Research conclusions： (1) The lateral deformation of the diaphragm wall is affected significantly by the time effect. The construction process should be optimized, and the brace should be added after the excavating. (2) The deformation increases deeply in the foundation pit excavation, and increases insignificantly while the station is in construction. The maximum velocity of the deformation occurs while the fifth layer excavates. (3) The period between the foundation bottom excavating and the bottom floor concreting is one of the main period for the deformation growth, in which period the performance increase much. The lateral deformation increments slow down and shape becomes to be stable after the bottom floor concreting. (4) The results are helpful for the design and construction of similar metro station engineerings. 