In order to study the deformation law of underground continuous walls in deep foundation pits of metro under complex engineering environmental conditions, this paper takes the main deep foundation pit of Fujian road station of Nanjing metro line 5 as the background. According to three conditions: whether the underground continuous wall enters the rock, the distribution of building loads on both sides, and the different thicknesses of the underground continuous wall, five typical sections are selected. The deformation law of the underground continuous wall is analyzed by using Plaxis 2D finite element modeling, and compared with the on-site measured displacement data of the underground continuous wall. The results show that the underground continuous wall entering the rock reduces the horizontal displacement of the overall enclosure by restricting the deformation of the wall toe, and the effect is more obvious with the uplift of the rock surface. Under the eccentric loading of the surrounding buildings of the foundation pit, there is a tendency for the upper opening to shift as a whole to the other side. The deformation of a 1000mm thick underground continuous wall is generally 1/5 to 1/3 smaller than that of an 800mm thick underground continuous wall. The loss of moisture in the soil within the foundation pit and the prolonged duration of each construction process will increase the deformation of the underground continuous wall. In addition, the end well of the station foundation pit is affected by the "spatial effect", and the result calculated by the planar model will be larger.