Twelve-year-old child early after urinating, the penis has been erect, most of the normal physiological phenomenon, may be into puberty in the body sex hormone secretion of the performance. The 12-year-old child may have entered the puberty development period, the body androgen secretion exuberant, easy to cause the erection of the penis, so it will cause the 12-year-old child early urinate after the penis has been erect. Now give the child correct sex education, avoid exposure to unfavorable sexual stimulation, go to do some outdoor exercise, go to do other things, divert attention. Adolescence should ensure sufficient and good sleep, strengthen the nutritional diet, diversification, appropriate exercise, if the symptoms of physical discomfort, but also timely medical treatment.