線上學習（又稱「遠距教學」）在各領域的應用近年來不斷成長，學校教育當中也有越來越多的課程使用線上學習來實施教學工作。因為線上學習有別於一般傳統教學，具有資訊科技的介入，因此線上學習能帶來那些有別於傳統面授的效益是研究者所關心的，希望能經由滿意因素比較研究，了解線上學習的效益。 本研究是採用關鍵事例法(CIT)所做的質性研究，研究對象是國立政治大學線上學習的使用者（包含學生、助教和老師），用電話訪談或面談的方式來蒐集使用滿意╱不滿意的事件。研究將線上學習課程分成「同步」、「面授錄影」、「面授與非同步」及「線上非同步」四種類型，並配合課程結構問卷，對學生學習滿意進行分析，接著再比較助教、老師的滿意因素，找出三者個別的滿意原因，再經由整合比較找出整體的滿意╱不滿意因素。研究發現： （一）影響學生線上學習滿意╱不滿意的因素，共有「教學熱誠和技巧」、「情感互動」、「回饋互動」、「知識互動」、「資訊傳輸」、「教學系統軟硬體使用」、「課程設計」與「非電腦類教室設備」八類。 （二）影響助教線上學習滿意╱不滿意的因素，共有「動機需求」和「資訊科技介入對工作績效影響」二大原因。其中，動機需求含有「工作報酬」、「成就」、「社會需求（對老師）」、「社會需求（對學生）」四類；資訊科技介入有「系統使用流暢性」、「系統功能對教學效果影響」與「教學支援」三類。 （三）影響老師線上學習滿意╱不滿意的因素，共有「正面效益」和「負面效益」二大原因。正面效益的方面有「科技效益認知(樂觀)」、「創新求變」二類，負面效益則有「功能存疑」、「適應不良」與「技術和人力支援」三類。 （四）科技介入對於學生助教和老師的滿意都會有影響，但影響不同。 關鍵詞：線上學習、關鍵事例法、學習滿意 / Distance- Learning (also called “E- Learning”) keeps in growing as it applies to each field in recent years, as well as more and more courses uses Distance- learning for teaching in school education. Distance- Learning differs toward Traditional Learning because of the infusion from information technology; therefore the efficiency that Distance- Learning brings which differentiates from Traditional Learning is concerned by researcher through comparing satisfaction factors in this study to understand the benefit of Distance- Learning. This study adapt Critical Incident Technique (CIT) as qualitative research, research subject is Distance- Learning users (contains student, teaching assistant and lecturer) from National Chengchi University, which uses telephone surveys or face- to- face interview to collect usage satisfaction/dissatisfaction incident. This study categories Distance- Learning into “Synchronous”、“Personal Instruction and Video Recording”、 “Personal Instruction and Asynchronous” and “Distance Asynchronous” by incorporating course structure questionnaire to proceed student satisfaction analysis, followed by comparing satisfaction factors from teaching assistant and lecturer to find out individual satisfaction factors. Through integration and comparison of overall satisfaction/dissatisfaction factors, study result shows: (1) Factors influence Distance- Learning students’ satisfaction/dissatisfactions are “Teaching Enthusiasm and Skill”、“Emotional Interaction”、“Feedback Interaction”、“Knowledge Interaction”、“Information Transmission”、“Distance- Learning System Hardware/Software Usage”、“Curriculum Design” and “Non- computerized class facility”. (2) Factors influence Distance- Learning teaching assistants’ satisfaction /dissatisfactions are “Motivational Needs” and “Influences of Information Technology infusion toward Work Performance”. There are “Working Salary”、“Achievement”、“Social Needs (to lecturer)”、“Social Needs (to student)” within “Motivational Needs”; while “Information Technology Infusion” has “Fluent usage of System”、“Influences of System Function toward Teaching Effect” and “Teaching Support”. (3) Factors influence Distance- Learning lecturers’ satisfaction/dissatisfactions are “Positive Efficiency” and “Negative Efficiency”. “Positive Efficiency” has “Recognition of Technology Efficiency (optimism)” and “Innovativeness”, while “Negative Efficiency” has “Insecurity”、“Discomfort”、“Technical and Human Support”. (4)Technology infusion influences students’、teaching assistants’ and lecturers’ satisfaction, but with different influence. Keywords: Distance- Learning, Critical Incident Technique (CIT), Learning Satisfaction