In order to reduce the subjectivity and uncertainty of pitch adjustment of thrust system of shield boring in inclined shaft, the settlement description of shield pitch is proposed based on foundation settlement, and the settlement description model of shield pitch in inclined shaft is established based on Winkler elastic foundation model. And then, the mathematical model for describing pitch adjustment ability of propulsion system of shield in inclined shaft is established considering the load effect, and the calculation conditions of upper and lower limit values are given. Finally, the influence of design slope angle on pitch adjustment ability of thrust system of shield is studied based on the abovementioned mathematical model, by taking the inclined shaft project of Taigemiao Coal Mine in Xinjie, Inner Mongolia for example. The study results show that: (1) With the increase of downslope angle, the upper and lower limit values of pitch adjusting ability of shield thrust system decrease continuously. (2) When the downslope angle continuously increases, the rapid growth of sliding force would induce the continuous decrease of pitch adjustment ability of shield thrust system.