Male penis 20cm is normal, penis in erect state is greater than 8cm belong to the normal range, it depends on the innate development, physiological function is normal that does not need any treatment. The male penis varies greatly from one individual to another, depending on factors such as race, height and nutritional status during development. Normally, the length of male penis is more than 8cm in the erect state and not less than 4cm in the soft state, which is a normal level, and thus a penis length of 20cm is also normal. The length of the penis mainly depends on the innate development, similar to the change of height, as long as the physiological function of the penis is normal, does not affect the normal urination and can have a normal sex life do not need to be dealt with.