According to the accurate problem of the wheel pressure detection, the pressure difference between the tail of the cylinder and the piston was deduced according to the N-S equation. The laminar flow state of the liquid in the cylinder was analyzed by MATLAB and the internal turbulence of hydraulic cylinders was simulated by using dynamic mesh method and κ-ε model of FLUENT. The influence of hydrodynamic factors on pressure detection was studied. The simulation and experimental results indicate that the difference between the static pressure at the bottom of the cylinder and the actual output static pressure at the piston rod is increased with the extension length of the cylinder rod. Reducing the extension length of the piston rod and quadratic curve fitting of the pressure can improve the accuracy of the press force detection.