Abstract: Under complex geological conditions, the pipe curtain method of advanced support structure ensures the safety of tunnel excavation construction. This paper, with the core area of the first phase of the cargo passage along the mountain - the Chengdu-Chongqing Expressway underpass project as the engineering background, elaborates on the installation method of jacking equipment in pipe curtain top-pipe construction, the correction control measures of the top pipe machine, the mud device for top pipe advance and retreat, the type of thixotropic mud, and the construction sequence of pipe curtain top pipes. It proposes specific construction parameters such as the slurry mix ratio for pipe canopy grouting and the control of grouting pressure. The research results show that by optimizing the sequence of pipe jacking and the mix ratio of thixotropic mud, the construction efficiency was increased by about 20%, the stability of the strata was significantly enhanced after 8 hours of grouting, the ground settlement was controlled within 5 millimeters, and the construction safety was significantly improved. The research findings can provide a reference for similar engineering construction at home and abroad.