一般認為1920年代臺灣興起近代政治運動，是受到大正民主風潮的影響。但是，何謂「大正民主」？大正時期有何重要思潮？又如何影響臺灣的反殖民運動？這方面的研究成果卻很少。 本文梳理大正民主時期的各種思想流派後發現，當時的主流思潮是折衷的自由主義、有限的民主主義，妥協於日本帝國架構與天皇體制，強力批判日本帝國主義擴張政策被視為過於激進。這些被稱為右派的保守派人士關心殖民地問題，要求改善殖民地統治，使之永遠為帝國領土。相反的，社會主義者因為錯誤的判斷，以為俄國革命成功、日本群眾運動興起，認為實現階級革命即將實現，因此，對殖民地問題並不關心。在此情況下，臺灣留學生較接近右派的自由主義者，並且從中取得思想資源。 同時，大正民主時期日本言論界批判殖民壓迫，關切的焦點是朝鮮、滿洲、中國，臺灣問題極少受到關注。臺灣留學生的回應戰略是，儘可能礦大聯合對象，左派走國際主義路線，與日本、朝鮮、菲律賓、印度等亞洲各國人士互動，更與朝鮮、中國無政府主義者、社會主義者攜手組織團體；右派也與朝鮮人合作辦刊物、相互聲援。20年代反殖民運動中的跨國合作情形，超乎想像，值得進一步研究。

There is a general viewpoint that Taiwanese' modern political movement launched in 1920s was affected by the wave of Taisho Democracy.However,what is the meaning of "Taisho Democracy"?What ideological trend spread in this period?How did it affect Taiwanese anti-colonial movement?There are few research results in related topics. This paper reviews the various thought trends in Taisho Democracy period,and discovers that the mainstream was a half-way liberalism and limited democracy which gave way to the Japanese imperialism and the emperor system.Strong critics on imperialism and expansion policy were regarded as radical.The conservative so called right wing,cared about the colonial questions and urged to improve colonial rule for keeping empire's territories.On the contray,the socialist didn't concern with colony topics attributed to the wrong judgment about success ofthe Russian Revolution,the rise of a mass movement in Japan,and believed that class revolution would be realized.Under this situation,Taiwanese students closed to the right-wing liberals and obtained ideological resources from them. Meanwhile,in Taisho Democratic period,the mass media criticized colonial oppression,focused on Korea,Manchuria and China,and paid little attention to Taiwan.The strategy from Taiwanese students was to maximize the cooperative objects.The left-wing chose internationalist route,interacted with Japanese,Koreans,the Philippines and the Indians in Asia,especially organized groups with anarchists,socialists from Korea and China.The right-wing also cooperated with the Koreans for publications.The trans-nation cooperative movements in 1920s are unimaginable and worthy for further study.