The pipe jacking method is widely used. In order to control the jacking force of the jacking process more accurately, the paper assumes that the grouting slurry is a viscous time-varying fluid, and divides the grouting process into two stages: initial injection and full injection. The model adopts the model of partial contact between pipe and soil during full filling, and proposes a criterion for judging the state of slurry based on the slurry diffusion area and seepage velocity, and establishes the whole process mechanical model of the pipe section considering the interaction between the pipe and the soil. When the slurry is full, based on the viscous fluid mechanics and the partial contact model of the pipe and soil, the shear stress of the different contact surfaces of the pipe section is obtained. On this basis, the buoyancy generated by the slurry is compared with the gravity of the pipe section to determine the shape of the pipe section under the joint working mode of pipe-soil-slurry, and obtain the mechanical model of the state of the pipe section under different shapes. Further calculation examples prove that under the condition of known other parameters, the jacking resistance of the pipe section can be calculated by the whole-process mechanical model of the pipe section proposed in this paper. Compared with the actual measurement and calculation results of other literature, it can be seen that the calculation model proposed in this paper can accurately reflect the working state of the pipe section in real-time, and the calculation results are more accurate and closer to the actual situation.