本文以「統一解釋法律之權限行使及其分權」為題，討論最高行政法院大法庭及司法院大法官行使統一解釋法律之權限。為此，鑑於行政法院組織法之修正、憲法訴訟法之增訂，本文之主軸，係論述三個核心問題：何謂統一解釋法律、如何為統一解釋法律之權限行使、如何為統一解釋法律之分權，以說明按行政法院組織法，最高行政法院大法庭於原因案件之確定終局裁判前，具有統一解釋法律之裁判權限，並發生具體性、個案性之效力，而按司法院大法官審理案件法（憲法訴訟法），司法院大法官於原因案件之確定終局裁判後，具有統一解釋法律之決議（裁判）權限，並發生抽象性、一般性之效力。然而，本文建議，憲法訴訟法施行後，司法院大法官組成憲法法庭進行審判工作，宜專注於與憲法解釋有關之權限行使，即取消司法院大法官統一解釋法律之權限行使，並將其任務交由終審法院大法庭或聯合大法庭處理，使得憲法第七十八條：「司法院……，並有統一解釋法律及命令之權。」所稱之「司法院」，不包括司法院大法官，以利司法院大法官致力於憲法解釋，而不再行使統一解釋法律。

This article is entitled “Exercising the Authority of Unified Interpretation of the Law and Its Separation” which aims at discussing how the Grand Chamber of Supreme Administrative Court and Grand Justices of Judicial Yuan exercise the authority of unified interpretation of the law. Because of the amendments of Organic Act of Administrative Court and Constitutional Court Procedure Act, the main axis in this article is to expound three core issues: what is the unified interpretation of the law, how to exercise the authority of unified interpretation of the law, and how to separate the authority of unified interpretation of the law. Accordingly, this article explains that Grand Chamber of Supreme Administrative Court, in line with Organic Act of Administrative Court, has the authority of unified interpretation of the law with concrete and specific effect before the final and binding judgment of causal cases. Similarly, Grand Justices of Judicial Yuan, based on Constitutional Interpretation Procedure Act (Constitutional Court Procedure Act), have the authority of unified interpretation of the law with abstract and general effect after the final and binding judgment of causal cases. However, this article suggests that Grand Justices of Judicial Yuan, after the implementation of Constitutional Court Procedure Act, will form Constitutional Court and exercise trial, so they should focus on exercising the authority of interpretation of the constitution. In other words, the unified interpretation of the law is no longer exercised by Grand Justices of Judicial Yuan and is left to Grand Chamber of Supreme Administrative Court (Supreme Court) or United Grand Chamber. This manifests the “Judicial Yuan” in Article 78 of the Constitution which enumerates that “Judicial Yuan … and has the authority of unified interpretation of the law and order” excluding Grand Justices of Judicial Yuan. Therefore, Grand Justices of Judicial Yuan are committed to the interpretation of the constitution, and are relieved of task to the unified interpretation of the law.