歌仔戲出身民間，在通俗商業劇場成長，為了適應求新求變的戲劇環境，長久以來，採用「幕表戲」的運作方式，以減省文字寫作和排練的麻煩，滿足大量新劇目的需求。歌仔戲即興劇場的運作的方式，無論是編創劇目或即興表演，都與十六世紀興起的義大利即興喜劇相類，形成有趣的對照。 歌仔戲堪稱當今東方最具代表性的即興劇場藝術之一，而演員「做活戲」則為其靈魂之所在。本文分兩部分，第一部分說明歌仔戲演員即興表演的機制和步驟。分析這一表演機制如何落實和依賴「演員中心」，並逐一說明其主要步驟的運用，包括：鋪陳戲劇場景、堆疊劇情、落歌等。最後綜合這三者，以實例說明歌仔戲演員如何將一段「臺數」立體化為一場演出。 第二部分介紹歌仔戲演員即興表演訓練的內涵和方法。首先介紹歌仔戲演員的學習項目，包括「合零為整」的教育劇目和橋段的技藝內涵，以及「化整為零」的「腹內」累積。接著分析演員養成訓練的程序，從戲劇環境的耳濡目染、上臺與開口訓練，到正式的腳色訓練。 總覽歌仔戲演員即興表演機制和養成訓練，本文將略述在此環境下，歌仔戲「拼貼」表演風格的形成，做為餘論。

Taiwanese opera (ge-zi-xi) originated as part of folk culture and developed as an art form in the commercial theater. In order to meet the demands of the ever-changing theatrical environment that valued innovation, it long ago adopted a performing style called “scenario＂（mu-biao-xi）to eliminate the trouble of writing and rehearsing and to meet the great demand of new operas. Improvisation in Taiwanese opera is similar to that in Italian comedy（Commedia dell'Arte）, which first became popular in the sixteenth century, whether in the creation of new plays or in improvising, and the two provide an interesting contrast to each other. Taiwanese opera can be viewed as the most representative Oriental art form of improvisation performance, and its essence lies in the improvisation of its actors. This article is divided into two parts: the first part is devoted to a description of the mechanism and the process of actors´ improvisation performance in Taiwanese opera. An explanation is provided, which shows how such performance works on the stage with the actors as its center and illustrates the main procedure in the improvisation performance, including setting up dramatic scenes, developing the plot, and singing. Finally, some examples are taken to show how the above three steps are taken up by actors of the Taiwanese opera to put on a scenario on stage. The second part introduces the essence and methods of the training required for the improvisation performance of actors in Taiwanese opera. The training process for actors includes developing a familiarity of some operas to increase their knowledge and acting skills in a cumulative manner. Further, the cultivation and training process is analyzed, including the effects of the dramatic environment on the actors, acting and singing practices as well as actual training for certain characters. After a discussion of the mechanism and training of the actors´ improvisation performances, a conclusion is drawn on the formation of the “mashup＂ style of performance in Taiwanese opera.