A large cross-section rectangular pipe jacking construction is used at the 8^th entrance and exit of one station in Zhengzhou Metro Line 3, which needs to vertically underpass a DN2000 sewage pipeline in near distance. The soil under the sewage pipeline bottom is reinforced with MJS construction method. Real-time monitoring of surface and pipeline displacement during the pipe jacking process is carried out, numerical simulation is compared with actual measurement results, and the accuracy of the numerical model and the rationality of MJS pipe bottom soil reinforcement measures are verified, With the help of three-dimensional numerical calculations, it is found that the surface settlement, vertical displacement, horizontal displacement, bending moment and shear force of the pipeline with MJS reinforcement can be reduced about 53.59%, 38.13%, 73.3%, 57.3%, and 48.02% respectively compared to the unreinforced soil, and so MJS can significantly improve the bearing capacity, density, strength, and elastic modulus of the soil under the sewage pipeline bottom, and fix and protect the pipeline. Further analysis is conducted on the impact of grouting replacement rate, reinforcement width, and reinforcement depth of MJS on sewage pipeline deformation, and recommendations are provided about grouting replacement rate, reinforcement width and reinforcement depth, which provide reference and inspiration for similar projects.