在合同义务未履行或履行不符合约定的情形下，债务人可通过主张履行费用过高，将债权人的继续履行请求权排除。《民法典》合同编580条对履行费用过高规则进行了规定，然而由于履行费用的概念模糊、过高判断标准不一，容易导致该规则适用的泛化。为了更好地理解履行费用过高规则，首先需要论证其正当性基础。其次，需要对履行费用过高规则在我国《民法典》合同编的体系定位进行分析，同时考虑到域外立法实践，对履行费用过高规则的立法原意与目的价值形成系统认识。明确履行费用的范围是进行规则适用的首要任务。应着重分辨额外费用与全部费用的边界，为避免将履行费用泛化造成对债权人利益的损害，应将履行费用的范围限定为额外费用。考虑到对债权人履行利益的保护和债务人的违约过错，在履行费用过高场合应将债务人情感利益与精神成本进行排除。在涉及到时间成本与劳务成本的情形下，可以采用货币化手段，将其纳入到履行费用范围。市场经济环境下，对于机会成本的纳入要更加谨慎，只有在涉及到社会公共利益、集体利益的情况下，可酌情考虑机会成本的影响，以此来避免道德风险。此外，还需要明确履行费用对于债务人的人身专属性，避免用第三人或社会一般标准来度量债务人的履行费用。在进行规则适用的时，需要以债务人给付义务存在和当事人合意约定缺失为前提。对于规则的判断对象，应将债务人履行费用和债权人履行利益作为比较对象。债权人利益中最主要的是债权人的经济物质层面的利益。在过高的判断标准上，从我国《民法典》立法构造和国外立法经验出发，应采用相对值比较，可酌情考虑超过130%作为“过高”参考基准。在审判和质证程序上，应按照《民事诉讼法》规定，由债务人承担履行费用过高的举证责任。在个案判决中，为了避免法条的僵硬化适用，应将动态系统论纳入，将司法实践中的特殊利益、可归责性、补救措施合理性、强制执行可行性等要素纳入考量，同时以合理负担偏离度、特殊利益偏离度、合同信赖偏离度为主要维度进行判断。最后，对履行费用过高规则的法律效果进行明确，形成履行费用过高适用的完整链条。

Where contractual obligations are not performed or performance is not in accordance with the agreement, the creditor has the right to request to perform.However, the debtor can exclude the creditor‘s claim by claiming that the cost of performance is too high. Article 580 of the Contract Part of the Civil Code stipulates the rule of excessive performance expenses, but due to the vague concept of performance expenses and different judgment standards, it is easy to generalize the application of the rule of excessive performance expenses. In order to better understand the rule of excessive cost of performance, the first task is to justify its justification. Secondly, it is necessary to analyze the system positioning of the rule of excessive performance expenses in the contract part of China‘s Civil Code, and at the same time take into account the extraterritorial legislative practice, and form a systematic understanding of the legislative intent and purpose value of the rule of excessive performance expenses.In order to clarify the application of the excessive cost of performance rule, it is necessary to clarify the scope of the cost of performance. Emphasis should be placed on distinguishing the boundary between additional expenses and full expenses, and in order to avoid the prejudice to the interests of creditors by generalizing performance expenses, the scope of performance expenses should be limited to additional expenses. Considering the protection of the creditor‘s performance interest and the debtor‘s fault for default, the debtor‘s emotional interest and moral cost should be excluded when the cost of performance is too high. In cases involving time and labour expenses, monetization can be used to include them in the scope of performance expenses. In the market economy environment, the inclusion of opportunity expenses should be more cautious, and the impact of opportunity expenses should be considered as appropriate when social public interests and collective interests are involved, so as to avoid moral hazard. In addition, it is necessary to clarify the personal exclusivity of the debtor for performance expenses, and avoid using third parties or general social standards to measure the debtor‘s performance expenses.When applying the rules, it is necessary to presuppose the existence of the debtor‘s obligation to pay and the absence of the parties‘ agreement. For the object of judgment of the rules, the creditor‘s performance interest and the debtor‘s performance cost should be compared on the basis, the most important of which is the creditor‘s economic and material interests. In terms of excessive judgment standards, starting from the legislative structure of China‘s Civil Code and foreign legislative experience, relative value comparisons should be used, and 130% can be considered as the "excessive" reference benchmark as appropriate. In the trial and cross-examination procedures, the debtor shall bear the burden of proof that the cost of performance is excessive, in accordance with the provisions of the Civil Procedure Law.In individual case judgments, in order to avoid the rigid application of legal provisions, the dynamic system theory should be taken into account, taking into account the special interests, attributability, reasonableness of remedies, enforcement feasibility and other elements in judicial experience, and at the same time judging by the deviation of reasonable burden, special interests, and contract trust as the main indicators. Under the conditions of applicable rules, the legal effect of the rule of excessive performance expenses is clarified, forming an overall chain of application of excessive performance expenses.