The invention discloses a structure of a penis thickening pad with mechanical adaptability and a preparation method. The penis thickening pad consists of thick-and-thin membranes and wraps the penis under the skin to form an annular O-shaped open tubular body. A thick ring is used for thickening the penis, and a thin ring is used for shortening and stretching. The O shape can expand and shrink; therefore, the pad can stretch, expand, shorten and shrink with adaptability along with physiological changes of erection and softening of the penis. The pad is mainly made of natural biomaterial with good biocompatibility and high stability, has good tissue compatibility after implanting, does not cause exclusive reaction, does not generate fiber cyst and cyst contracture, induces tissues of a patient to grow in the pad, and finally achieves the thickening of self tissues.