In the post-Cold War era, the complexity of this dynamic security environment challenges the conventional national security awareness. State or non-state actors have leveraged the traditional and non-traditional means to blur the boundary between war and peace. In 2014, the Ukrainian crisis triggered academic debate over "hybrid conflict." The hybrid threats utilize unconventional ways. This paper analyzes the evolution of the threat patterns in the international security environment, in order to clarify the concept of hybrid threats, and explore the attack methods used in combination. Then, the author refers to the United States and NATO policy responses, and analyzes the thinking of adjustment for development of Taiwan's military missions and the problems that Taiwan may face after the adjustment. The entire report will serve as a policy recomendation for government decision making.