應用自我決定理論的「社會情境→心理中介→動機型態→行為結果」動機過程模式，探討其在體育志工參與行為上的適用性，同時評估各相鄰變項間的影響效果。方法：以便利取樣方式對14 個縣市體育場志工進行問卷調查，總計發出700 份問卷，回收619 份，有效問卷507 份。調查工具包含自主感支持、控制、基本需求滿足、參與動機及行為意圖等量表，並以線性結構方程模式推估模式之各項估計值及適合度。結果：經統計分析後發現，除控制與關係感的徑路估計值未達顯著水準外，其餘各變項間之影響效果均獲得證實，並且整體模式的適合度也在可接受的範圍內。結論：想要留住志工，首要之急就是要提供自主感支持的情境，這是因為自主感支持的情境會對個人的基本需求滿足帶來正面影響，其後內化個人動機型態，影響行為意圖；至於控制的情境所得結果正好和支持情境相反。根據上述發現，除給志工業務辦理單位提供實務應用之建議外，也對未來研究的可行性方向提出說明。

Based on self-determination theory, the purpose of this study wasattempted to propose and test a motivational process model of sport volunteers whichwas following the processes of “social situation factors → psychological mediators→ types of motivation → behavior consequences”. Methods: Using convenientsampling method, a group-administrated questionnaire was sent to 700 sport volunteersserved at 14 county stadiums. Out of the 619 questionnaires returned, 507 of themwere valid. Research instruments used in this study were autonomy support scale,control scale, basic need satisfaction scale, motivation scale, and behavioral intentionscale. LISREL was used to estimate the parameters and model fit. Results: Structuralequation modeling analysis showed that the final model fit the data satisfactorily andall parameters were significant except for the path linked control situation torelatedness. Conclusion: The most important thing for orgnaization to retainvolunteers was to provide a autonomy-support context that positively impacted basicneed satisfaction. When satisfied of these needs yielded internalized self-determinedmotivation and positively behavioral intention, but when thwarted led to diminishedmotivation and negatively behavioral outcome. Based on the finding above, someadvices were proposed for the managers of volunteer organizations. Lastly, futureresearch orientations were also proposed.