Abstract: For large-aperture primary mirror hydraulic support system, a simple and reliable precision guiding mechanism is needed to give a larger stroke range (mm) for cylinders, which did not require lubrication and maintenance. In this paper, a flexible metal membrane was designed for the cylinder guiding and radial positioning. With the method of finite elements and nonlinear geometry algorithms adopted, an analysis was carried on the flexible membrane with different topologies, it was shown that V-shape metal membrane could well overcome stress stiffening and maintain the stability of flexibility; with flexibility as the optimization target, optimize the V-shape position and geometry dimensions of membrane V-shape, and the guiding flexibility of metal membrane was improved by 14.2%; established the experimental platform, did experiments and verify the simulation results. According to the experiment and simulation results, the V-shape membrane is found not only having a good flexibility in the vertical surface direction, but also ensuring the stability of flexibility by avoiding stress stiffening. These founds give a certain guidance in the design and application of the guiding mechanism for hydraulic support cylinders and active micro-displacement actuator.