本文首先阐释了不溯及既往原则的概念及其核心价值，梳理了自纽伦堡审判以来，国际刑事司法机关是如何提出、应用并阐释不溯及既往原则的适用范围的。随后，本文分析了不溯及既往原则在《罗马规约》当中的体现，讨论了这一原则的缔约历史和适用状况。最后，本文着重讨论了第12条第3款的特别声明对该原则的挑战，分析可以采取哪些方案解决这一问题以及这些方案的优劣。最终结论是，即使在特别声明溯及既往的情况下，也应当适用《罗马规约》本身。

This article first explains the concept and core value of the principle of non-retroactivity, and sorts out how international judicial organs have proposed, applied and explained this principle since the Nuremberg Trials. Subsequently, this article analyzes the embodiment of this principle in Rome Statute, and discusses the contracting history and application of this principle under ICC legal framework. Finally, this article focuses on the challenge to this principle posed by ad hoc declaration could be made under Article 12(3). In the conclusion, the article proposes some possible solutions to this challenge, and evaluates advantages and disadvantages of different approaches.