The invention discloses a sliding-leakage-prevention viscous fluid damper. The damper comprises two volume adjustable sealing cavities, two shell assemblies, a spring and a guide rod, wherein the twovolume adjustable sealing cavities are in butt joint, one or more damping holes used for enabling the two volume adjustable sealing cavities to communicate with each other are formed in the butt jointsurface of the two volume adjustable sealing cavities, each of the two shell assemblies is of a cylinder structure with one open end and one pored end, the open ends of the cylinder structures are oppositely arranged and are correspondingly arranged at the peripheries of the two volume adjustable sealing cavities in a sleeving mode, the butt joint parts of the open ends of the cylinder structuresare detachably connected, the two volume adjustable sealing cavities are corresponding in sliding fit with the inner wall surfaces of the corresponding shell assemblies, one end of one volume adjustable sealing cavity is fixedly connected with one end of the guide rod, the other end of the guide rod extends out of the pored end of the shell assembly A, one end of the other volume adjustable sealing cavity is fixedly connected with the end, in a compression state, of the spring, and the other end of the spring abuts against the inner bottom surface of the pored end of the shell assembly B. According to the sliding-leakage-prevention viscous fluid damper, the sliding fit position does not need to be additionally provided with a sealing design, and the damping performance can be adjusted ina large range.