Abstract: In view of the problem that the pressure fluctuation of the large cavity of the steel support axial force servo cylinder cannot be qualitatively monitored for deformation of the enclosure, the built-in pressure sensor and MT magneto-type displacement sensor are adopted to optimize the structure of the steel support servo cylinder, and the pressure and displacement signals of the large cavity of the cylinder are collected at the same time. When the large cavity pressure change ΔP and the displacement of the piston rod of the cylinder ΔS exceed the preset amount, the system sends an early warning signal. The practice has proved that this scheme can greatly reduce the frequency of false warning of the original system, and ensure the deformation of the construction enclosure. The feasibility of the design model is also verified. It can provide a reference for structural design of the steel support axial force servo cylinder.