臺灣歌仔戲是目前東方戲劇中，保留「幕表戲」即興演出最完整的劇種。「幕表戲」的編劇和表演方式，原為許多地方戲曲所普遍採用。1951 年，大陸為了強化戲曲的政治宣傳效果，推動「戲曲改革」，由政策主導，以負面評價、不鼓勵的方式，促成幕表戲的消失；在臺灣，為了提升歌仔戲的藝術位階，本土戲曲工作者亦多主張追求「精緻化」，提起廟會野臺的「幕表戲」，同樣抱着質疑的態度。事實上，「幕表戲」的編創和演出，對於演員，既是演技的呈現，同時又是能力的開發。這套發展自民間的戲劇編創機制，是臺灣戲曲珍貴的資產，值得我們重視和保留。 本文試圖為歌仔戲幕表戲尋找定位。為了避免侷限在單一文化，或甚至單一劇種的框架中，本文探索歌仔戲「幕表制」的可能來源，回溯戲曲幕表戲生成的歷史，並參照西方劇場即興戲劇的歷史和當代發展情形，援引西方學界和劇界面對即興戲劇的態度和研究。從這樣的立足點，探尋歌仔戲幕表戲藝術存在的意義、研究的視野，和劇場運用的可能性。 首先，回顧中西戲劇史中的即興戲劇，探索幕表戲的形成。進一步，分析當今即興戲劇的三大脈絡，指出臺灣歌仔戲幕表戲在中西即興戲劇歷史和當代脈絡中的位置。接着，在幕表戲的範圍內，以西方幕表戲最具歷史和代表性的義大利即興喜劇（commedia dell’arte）與歌仔戲做對照，凸顯歌仔戲幕表戲的藝術特色。並以西方學界及劇界對幕表戲及其他即興戲劇的研究和運用為借鑑，檢視歌仔戲幕表戲的相關研究及視野，及其與當代劇壇連結的可能性。

Among the many Oriental dramatic forms, Taiwanese Opera is the one that actually practices spontaneous performance with its “mubiao-xi”(scenario-based performances). In fact, many local dramatic forms used to adopt “mu-biao-xi” for scripts and stage performances. In 1951, to reinforce political propaganda by means of drama, China promoted “dramatic innovation” with policies that discouraged performances of “mu-biao-xi” through negative commentary, which hastened the disappearance of such performance art in China. In Taiwan, to uplift the artistic level of Taiwanese Opera, those who work in the field insist on the refinement of Taiwanese Opera techniques and have long had a suspicious regard for “mu-biao-xi” which is performed outdoors at temple festivals. As a matter of fact, the writing, creation, and performance of “mu-biao-xi” serves both to present and cultivate actors’ skills. This dramatic mechanism of writing and creating developed among the people is a precious resource of Taiwanese drama that calls for preservation and more consideration. This study evaluates “mu-biao-xi” by exploring the possible origin of “mu-biao-zhi” (mechanism of the scenario-based performances) in Taiwanese Opera, tracing the beginnings and evolution of “mu-biao-xi” in drama, and examining the history of and recent developments in improvisational theater in the West with references from Western academia and drama studies concerning their attitude and research on improvisational theater. At this point, I explore the significance of “mu-biao-xi” as an artistic form in Taiwanese Opera, the research dimensions of its performance, and the possibilities of its dramatic practice. This study first presents the history of improvisational theater in both Chinese and Western drama and the origin of “mu-biao-xi.” Then it analyzes the three developments of contemporary improvisational theater and points out the position of “mu-biao-xi” of Taiwanese Opera in the improvisational theater of both Eastern and Western drama and its contemporary development. Next, within the scope of “mu-biao-xi,” contrasting Italian “commedia dell’arte,” a most distinctive form of Western “mu-biao-xi,” and Taiwanese Opera clearly reveals the artistic characteristics of the “mu-biao-xi” of Taiwanese Opera. Finally, the study examines related works and views on the “mu-biao-xi” of Taiwanese Opera by applying Western academic and theater research and practice on “mu-biao-xi” and other forms of improvisational theater, and explores the possibility of combining such performances with contemporary stage performances.