Abstract: Whether discharge of sewage conforming to standards should take criminal responsibility depends on the new negligence theory and the old negligence theory. The old negligence theory emphasizes on foreseeable obligation to results and havs relatively low threshold to incrimination. According to this theory, discharge of sewage conforming to standards sewage can constitute a crime. The new negligence theory stresses on the duty of avoiding results and the threshold to incriminate is relatively high. According to this theory, discharge of sewage conforming to standards isn't established as criminal negligence. Discharge of sewage of enterprises doesn't meet the applicable conditions of the new negligence theory and will cause difficulties to justice. Therefore, in discharge of sewage, the old negligence theory should be applied in order to protect the ecological environment.