The Cross-Strait Service Trade Agreement, also abbreviated CSSTA and sometimes alternatively translated Cross-Strait Agreement on Trade in Services is a kind of agreement between Mainland China and Taiwan, signed in June 2013. Currently this 'agreement' is not only unratified by the Taiwanese legislature but also severely criticized in Taiwan such as Sunflower Student Movement, occupying the Legislative Yuan to raise their concern about the trade accord, March 18, 2014 students occupied the Legislative Chamber of the ＂318 sunflower student movement＂, there is a need to take a closer look at this 'agreement': what kind of status is this 'agreement'. Specifically, is this 'agreement' a law, an order, a treaty, or an administrative agreement or even a special agreement between Mainland China and Taiwan? In this paper, I am going to clarify this controversial issue. Firstly, the two sides signed a brief description of the historical background of the case, ＂serving free trade agreement＂, followed by analysis of the two sides signed the relevant agreements which have different interpretations of the nature of legislation, in practice there are different works. Taiwan's Executive Yuan recognized ＂service trade agreement＂ only and belong to an executive order, only to send the Legislative Yuan for reference. Legislative Yuan KMT group advocated ＂service trade agreement＂ is the nature of ＂quasi-treaty＂ shall be subject to the Legislative Yuan to complete the second reading review, but you can not make. After different perspectives are stated, I will then clarify whether these agreements are laws, orders, treaties, or administrative agreements or even special agreements.