Based on groundwater dynamics, the tunnel grouting process was analogized with the movement of groundwater towards a complete well, and a seepage model was established under layered geological conditions. By using the conformal transformation method, the problem was transformed from a planar radial flow to a planar uniform flow, and the analytical solution of the seepage field under layered geological conditions was solved. On this basis, the tunnel grouting model was simplified into three layers of strata, and analytical solutions were obtained for the tunnel seepage flow rate, external water pressure of the grouting ring, and external water pressure of the lining. To verify the effectiveness of the solution, the equivalent area method was used and numerical simulations were conducted against the background of the unity tunnel. The results show that with an increase in the thickness of the grouting circle and a decrease in the permeability coefficient of the grouting circle and lining, the water inflow and external water pressure of the tunnel will decrease, while the water blocking rate and external water pressure of the grouting circle will increase. Through error analysis, it was found that compared with the analytical solution, the error of the concentric circular section decreases with the increase of the thickness error of the grouting ring, while the error of the six centered circular section decreases. The simulation solution show that the water inflow of the two sections is close to 59%. As the permeability coefficient of the grouting ring decreases, the relative error between the simulated and analytical solutions for water inflow is relatively large. As the permeability coefficient of the lining decreases, the simulated solutions for water inflow and external water pressure of the lining are greater than the analytical solutions.