一、口头证据规则概述口头证据规则,是合同法和民事证据法中的一项重要而具体的证据适用规则,是指案件内有做成文书的合同、契据、遗嘱、担保等其他较为重要的文书时,法律不允许当事人一方以口头证据否定、限制、增加该文书在法律上的效力,除非当事人可以在协商一致的基础上,以新的书面合意变更或废除该书面合同等,否则,该文书具有绝对的证据力,任何证据不得否定或推翻它。即“当双方已合意订立书面契约后,契约内容之解释,须以契约内文字为准, I. Oral Evidence Rules General Oral Evidence Rules is an important and specific application rule of evidence in the Contract Law and Civil Evidence Law. It refers to the more important contractual, deed, will, guarantee and other important documents Instruments, the law does not allow one of the parties to verbally nullify, restrict or increase the legally enforceable effect of the instrument by oral evidence unless the parties may, on a consensual basis, alter or repeal the written contract with a new written agreement or otherwise The instrument has absolute evidence that no evidence can deny or overturn it. That is, ”When both parties have agreed to enter into a written contract, the contractual content shall be interpreted in the contractual language,