Construction of asymmetric load foundation pit adjacent to railway has a great impact on railway operation, and its deformation should be strictly controlled to reduce the impact on railway. Therefore, the design of foundation pit retaining structure is usually "conservative", and there is a possibility of optimization. In order to explore the possibility of retaining structure optimization in asymmetric load foundation pit, based on a project, the deformation and internal force of the equal-length pile retaining structure and the long-length pile retaining structure on both sides of the railway were tested, and the measured results of the two sides of the pile retaining structure were compared and analyzed. The results show that in this project, the deformation of the left and right sides of the foundation pit is small, both within the controllable range, and both the equal-length pile enclosure structure and the long-length pile enclosure structure can ensure the safety of the foundation pit and railway.Compared with the equal-length pile envelope, the maximum horizontal displacement and bending moment of the long and short pile envelope increase with the maximum horizontal displacement increase of 0.25 mm and the maximum bending moment increase of 10.14 kN·m, both of which are small. The long and short pile envelope has a good supporting effect. The horizontal displacement and bending moment of the short and long pile envelope adjacent to the asymmetric load side are larger than those far from the asymmetric load side, but the difference between them is small, and the influence of the asymmetric load on the short and long pile envelope is small.