最高法院民事大法庭2019年終於對原住民土地買賣作出重要決定，依108年度台上大字第1636號裁定意旨，認非原住民過去取得原住民保留地所有權之效果，違反禁止規定，依民法第71條本文規定，應屬無效。本裁定一刀兩切方式對於長期使用狀態宣告無效後，其原始買賣契約給付價金債權倘逾15年請求權時效，如此權利人又將如何請求返還原始給付價金？其衍生新的債權、債務，及租賃權、地上權紛擾將層出不窮？本文將從理論與實務層面作為依據，自原住民生活之環境土地、歷史背景、地上權法制、時效期間、借名登記、強制禁止規定等概念，探討大法庭該裁定之合理性與適法性，提出以重視原住民地上權或租賃權人土地目的用途，對已依法設定之最高限額抵押權仍應予尊重並維護，積極重新檢討原住民土地使用現狀等作為結論與建議。

An important decision about land transactions among aborigines was eventually made by Civil Great Chamber of Supreme Court in 2019. Based on contents of the 2019 Ruling Ref. Taishangda No. 1636, effects of acquisition of title of lands in aboriginal reserves by any non-aboriginal individuals in the past shall be invalid according to the main text of Article 71 of the Civil Code for violating the said prohibitive provisions. After the long-term use status being declared invalid by such a one-size-fits-all ruling, if the 15-year prescription period for the claim of payment in the original contract has become extinguished, how will obligees request return of the original payment? Will conflicts arisen from derived claims, debts, lease rights, and superficies emerge one after another? Based on dual theoretical and practical aspects, this article will probe into rationality and legality of the Ruling by Civil Great Chamber in terms of aborigines’living environment, land, historical background, legislation of superficies, prescription period, nominee registration, and the invalidity of mandatory and prohibitive provisions. Conclusions and suggestions will be focused on aborigines’ superficies and purposes of land use of leaseholders, respecting and safeguarding the maximum mortgage rights created in accordance with laws, and active re-examination of current land use status of the aboriginal lands.