本研究承襲組織人口學與組織公民行為的研究脈絡，探討國軍軍官人口結構的轉變對組織公民行為的影響，主要回答二項問題：(1)．國軍軍官人口結構的變遷過程為何？(2)．國軍軍官在不同的人口結構狀態下，其與組織承諾對組織公民行為的關係為何？經由國軍相關的歷史檔案分析，本研究將國軍軍官的人口結構變遷大致區分為常備軍官合理期（民國60年以前）、常備軍官衰退期（民國60-80年）與軍官人口組成多元期（民國80年以後）等三個階段。在這樣的基礎上，經採國軍軍官642份有效問卷為樣本，應用多元階層迴歸模型與分組迴歸係數檢定來檢證國軍軍官在不同人口結構狀態下，其與組織承諾對組織公民行為的關係，結果發現：(1)．人口組成結構會直接影響國軍軍官的組織公民行為，也會影響軍官對組織的承諾，進而影響其組織公民行為。(2)．相較於常備軍官衰退期與軍官人口組成多元期，常備軍官合理期的國軍軍官，其對組織的承諾度最高，進而其組織公民行為最佳；其次是常備軍官衰退期；最後則為軍官人口組成多元期。

This study extends previous literatures on organizational demography and organizational citizenship behavior(OCB) to reply two research questions in armed forces: (1). what is the transformation process of organizational demography. (2). What are the relationships among organizational demography, organizational commitment, and OCB. To reply above questions, first, we distinguished into three transformation stages of organizational demography: the reasoning period, the decline period, and the diversification period by archival data discussion for voluntary officers in armed forces: Second, based on above three stages, we will go a step further to explore the relationships among organizational demography, organizational commitment, and OCB by multivariate hierarchy regression model and Chow test. Results indicated: (1). The effects of organizational demography on OCB do not seem to disappear even after organizational commitment is introduced as an intervening variable, suggesting a robust direct effect of organizational demography on OCB. (2). Contrary to the decline and diversification period of voluntary officers, the higher organizational commitment were, the more OCB were, therefore the better organizational performance for the reasoning period of organizational demography of officers, then it was the decline period of voluntary officers, and last it was diversification period of voluntary officers.