The penis erectile diameter is only 3cm, is belong to the normal size. The size of the penis erection individual differences, there is no specific regulations, the diameter of the general in 2.5 ~ 3.5cm are normal, the length is greater than 8cm generally can be normal sex life. Penile erection diameter of 3cm, as long as the normal erection can be normal sexual life, sexual life process both husband and wife can get orgasm, sexual satisfaction is a normal physiological phenomenon, there is no need to fixate on the thickness and length of the penis, the function of the normal do not need to worry about and treatment. If you have erectile dysfunction, or abnormal intercourse time, abnormal libido, you need to go to the hospital in time for examination, to clarify the cause of the disease and follow the doctor’s instructions for treatment.