Suddenly the penis is not hard, that is, erectile dysfunction, may be overworked, mental and psychological factors, acute injury and other factors. 1. Excessive exertion: men who are overworked and fatigued at work and in life will suddenly experience erectile dysfunction during sex, which can be improved after reasonable rest. 2. Mental and psychological factors: too much mental and psychological pressure and conflicts between husband and wife may have a psychological impact on men, which may lead to erectile dysfunction. 3. Acute injury: Acute injury to the penis, resulting in local nerve damage, will cause men to have erectile dysfunction, thus unable to have a normal sex life. Suddenly the penis is not hard also seen in other reasons, if the duration is longer and there are other abnormal manifestations, it is recommended to consult a doctor for appropriate examination and treatment.