The invention provides a continuous change type integral piston ring mechanical loading device. The device comprises a piston, a loading device shell, a loading ejector rod and a connecting ejector rod, wherein the loading device shell is arranged on the top of the piston, a spring component installation hole is formed in the loading device shell, a spring component is installed in the spring component installation hole and comprises an outer spring fixture, an inner spring fixture and a spring, and the spring is located in a hollow structure formed by the outer spring fixture and the outer spring fixture; one end of the loading ejector rod is connected with the outer spring fixture, the other end of the loading ejector rod makes contact with a piston ring, a screw protrudes out of the middle of the loading device shell, an adjusting nut is installed on the screw, one end of the connecting ejector rod is connected with the inner spring fixture, and the other end of the connecting ejector rod makes contact with the adjusting nut. The integral piston ring can be loaded, uniform continuous quantitative loading of the peripheral direction of the piston ring is achieved, and relative elastic contact between the piston ring and a cylinder jacket is guaranteed.