中國民用航空局於2018年元月逕自開設、啟用接近於臺灣海峽中線「M503航線北上運行及相關銜接航線」，引發我國政府（臺灣）嚴正抗議，遂使此民航事務議題延伸至兩岸關係與國家安全問題，牽動兩岸互動走向。本文從臺灣海峽適用之「航行制度」與「領域管轄權」視角，分別釐清兩岸雙方在「法律」與「航空管理」層面的認知差異與爭執焦點，試圖建立在一個共同基礎上的學理探討。最後，築基於本文分析，作者研提政策建議，嘗試拋出「中立化民用航空區」(Neutralized Civil Aviation Zone)的構想，期望能提供兼具政策論述與實務操作的參考。

The China’s Civil Aviation Administration fully activated the northward route of the Airway M503 and its connecting routes of W121, W122 and W123 in Jan, 2018. This action has caused continuously severe protest from Taiwan Government given the airway is very close to the midline of Taiwan Strait. Therefore, this issue has been promoted from the level of civil aviation to national security level in Taiwan. This situation has worsened the tangled cross-Taiwan-Strait relation. In order to clarify the nature of this issue, this paper first uses the technical angles of Air Traffic Management (ATM) and territorial jurisdiction to distinguish the different understandings and argument from both legal and political perspectives of China and Taiwan. After distinguishing the difference and argument of this issue, this paper intends to conduct an academic study base on a common basis. Last, based on our analysis, we proposed a new concept of ＂Neutralized Civil Aviation Zone＂ which is built by using two parallel airways namely the M503 and a relocated L1. Therefore, we argue this air traffic controlling practice is able to be considered as that the both government have a fuzzy mutual acquiescence in recognizing the existence of the Midline of the Taiwan Strait. We also make some policy suggestions and we do hope these suggestions are able to provide authority and other scholars both theoretical and practical reference ideas.