Abstract: The irreparable harm is the core of the standard of conduct preservation and in the problem of blurs theory and practice.It's necessary to discuss the concept and discretion about it.Based on the analysis on the current experience in China and comparative studies,the classic and current theories consider the irreparable harm is the harm that cannot be repaired with substantive remedies and final specific remedies.The method of evaluating the harm could be thinking about if there is enough damage and if the damage is evaluable.