If it is during the pubertal development period, you can promote the development of penis by strengthening physical exercise, supplementing nutrition, and supplementing androgen if necessary; if it is in the sexual maturity period, the penis will not continue to develop, you can consider surgical treatment. 1. Pubertal development: pubertal development is the main stage of male penile development, this period can be strengthened through physical exercise, supplementation of high-protein food to promote the body’s androgen secretion to promote the development of the penis. If there is a lack of androgen in the body, you can follow the doctor’s instructions to supplement androgen. 2. Sexual maturity: After 18 years of age, men enter the sexual maturity stage, and the development of the penis begins to become slow until it stops developing. If you have a small penis, which affects your normal sex life, you can consider surgery to extend and enlarge your penis. Overall, penis size is affected by a number of factors, and the treatment is different at different times. If you have a small penis, you need to go to the hospital and have it treated under the guidance of a professional doctor.