Abstract: The judicial interpretations promulgated in recent years grant rights to people with expertise (experts) testifying in court，which has gone beyond the original intention of the procedural law, and the role positioning and opinion nature of experts need to be re-examined and defined. In order to protect the right of cross-examination, the legislation should not set obstacles for the defendant to apply for expert appearance in court. The current legislation does not require that experts testifying in court must have the qualification of appraisers, but it does not mean that experts do not need to have the conditions to reflect their professional knowledge advantages, only in this way can the opinion rule be applied. The basic function of experts participating in court hearings is to assist one party to cross-examine evidence, thus testifying is an expanded function entrusted to experts by judicial interpretation. The existing regulations lead to the ambiguity of the role of experts, and there are some restrictive factors in the process of the transition from expert assistant to expert witness, such as litigation structure and legalism of evidence. The opinions of testifying in court have a multi-layer nature of attribution, and the opinions regarding expert opinions can be understood as the refutation of evidence. The nature of expert opinions on specialized issues is similar to counterevidence, such opinions have the attribute of evidence, which can be classified into the category of specialized evidence to be cross-examined.

Key words: person with expertise, expert assistant, expert witness, specialized evidence

摘要： 近年来颁布的司法解释赋予有专门知识的人（专家）参与庭审过程的权利已超越诉讼法预设的初衷，专家的角色定位与意见归属亟待重新审视和界定。为保护质证权，立法不应对被告人申请专家出庭设置障碍。现行立法不苛求参与庭审的专家须具备鉴定人资质，但不意味专家毋庸具备体现专业优势的条件，唯此才能适用意见规则。专家参与庭审的基本职能为辅助一方质证，作证是司法解释赋予专家的扩张职能。现有规定造成专家的角色定位模糊，专家辅助人向专家证人转型的过程存在诉讼构造、证据种类法定等制约性因素。专家参与庭审发表意见具有多元化的性质归属，对鉴定意见提出意见可理解为对证据的反驳。而专家对专门性问题提出意见性质上类同于反证，此类意见具有证据属性，可归入专门性证据范畴接受质证。

关键词: 有专门知识的人, 专家辅助人, 专家证人, 专门性证据