国际法上的有约必守原则起源于古老的国内民商法原则,随后,其对于维持国际秩序的稳定、促进国际交往的优势日渐突显,并最终成为国际法的一项基本原则。然而受制于自身的局限性,加之国际形势的不断变化,有约必守原则的适用一度受到挑战从而陷入了困境,本文主要从有约必守原则的理论基础、有约必守原则的困境、有约必守原则的出路、以及当今的热点问题即“高铁走出去战略”中的违约对策四个方面进行探讨,从而对有约必守原则进行深入分析。 The principle of necessity and necessity in international law originated from the ancient principle of civil and commercial law. Subsequently, its principle of maintaining the stability of the international order and promoting international exchanges became increasingly prominent and eventually became a basic principle of international law. However, subject to its own limitations and the ever-changing international situation, the application of the doctrine of necessity must be challenged and thus in a dilemma. This paper mainly analyzes the necessity of the principle of “ There is a way out of the principle of about necessity and the hot issue of today is to discuss the four aspects of the ”default strategy“ in ”the strategy of going out of the high-speed rail" so as to conduct an in-depth analysis of the principle of necessity and necessity.