歷史上使役動詞的虛化演變相當頻繁多元，曾發展出致使、被動、假設和縱予四種用法。本文將根據此類動詞的歷史發展綜合探討虛化現象，並分別從句法、語義和語用三層面切入。觀察顯示，這三個層面所能掌握到的虛化特性各不相同：句法層面有利於掌握虛化的條件，語有層面有利於掌握虛化的方向，而語用層面則有利於掌握虛化後的發展。本文將根據使役動詞的多重虛化提出多項證據支持上述主張，為求論述周延，文中亦涉及其他相關句式的發展或特性，包括連動結構、致使義處置式等。

Historically, shiyi (causative) verbs have grammaticalized into multiple syntactic functions, including causative, passive, conditional and concessive conditional ones. Focusing on the poly-grammaticalization of shiyi verbs, this paper aims to illustrate the different functions which the perspectives of syntax, semantics and pragmatics serve in unveiling the properties of grammaticalization. By looking at the aspect of syntax, it helps investigate the conditions for grammaticalization; from the perspective of semantics, it helps examine the direction of grammaticaliztion; finally, from the perspective of pragmatics, it helps analyze the subsequent development of each syntactic function. For each argument, empirical evidence will be provided from the poly-grammaticalization of shiyi verbs. In order to draw a complete picture, this paper also refers to the serial verb constructions, the causative disposals, etc.