The invention relates to a thin polymer film surface periodical gradual changing microstructure eccentric roller pressing device and method. The eccentric roller pressing device comprises a machine frame, an eccentric roller pressing mechanism arranged on the machine frame, an unwinding mechanism and a winding mechanism, wherein the unwinding mechanism and the winding mechanism are arranged on thetwo sides of the eccentric roller pressing mechanism correspondingly; a thin polymer film material is arranged in the unwinding mechanism, one end of the thin polymer film material penetrates throughthe eccentric roller pressing mechanism and then is wound in the winding mechanism, and periodical gradual changing microstructures are machined on the surface of the thin polymer film material through the eccentric roller pressing device; and the machining method comprises the steps of unwinding, eccentric roller pressing and winding in sequence. Compared with the prior art, the surface of the thin polymer film is imprinted through eccentric mold rollers, second-stage microstructures are obtained on periodical first-stage contours formed through eccentricity of the mold rollers and are periodical gradual changing second-stage composite structures, the structure design is flexible, machining of different gradual changing microstructures can be achieved, and the demands with various continuously changing functions on different application occasions are met.