<p>The pipe-jacking construction has the characteristics of strong adaptability and high construction efficiency, and has been widely used in underground engineering construction. The jacking force is an important parameter in the design and construction of pipe jacking. To reduce the jacking force, the mud is often used to transform the pipe-soil frictional resistance into the pipe-mud frictional resistance. To study the pipe-mud frictional resistance, the mud was assumed to be an improved power-law fluid. Considering the gravity and flow direction of the mud, a non-uniform annular mud pressure model was constructed in the filling stage. Then, by incorporating the tortuosity effect of the soil layer, a calculation model of the pipe-mud frictional resistance was obtained. The factors affecting the pipe-mud frictional resistance were discussed. The results revealed that the pipe-mud frictional resistance was negatively correlated with grouting pressure, grouting time, and permeation coefficient. Conversely, it correlated positively with hydrostatic pressure and tortuosity. The influence of the permeation coefficient, grouting pressure, and grouting time on the pipe-mud frictional resistance was greater than that of the tortuosity and hydrostatic pressure. Finally, the calculation model of the optimized pipe-mud frictional resistance was verified by a practical engineering case. The results show that the error between the optimized pipe-wall frictional resistance and the measured data was 5.07%, which proves the rationality and accuracy of the calculation model. This research can provide theoretical guidance and a technical reference for calculating the pipe-mud frictional resistance in pipe-jacking.</p>