When men experience a sudden inability to have an erection during sex, different rest periods should be determined depending on the cause and cannot be generalized. If the cause is clearly identified and actively corrected accordingly, most patients can recover usually after a few weeks or months of rest. In men with normal erections during sex, the sudden onset of erectile dysfunction requires further clarification of the associated etiology. It may be related to recent stressful work life or change in work life environment, as well as recent over-indulgence and other factors. By actively correcting the relevant adverse factors, such as reducing psychological stress, relaxation and other adjustments, the phenomenon of failure to have normal erection can gradually be improved. Most patients can recover in a few weeks after active intervention, but it may take a month or even a few months to fully return to normal in long cases. In conclusion, men who suddenly cannot get hard need to develop good lifestyle habits and avoid staying up late and drinking alcohol. If conservative treatment does not work, it is recommended to actively seek medical advice to clarify the cause.