本研究的目的，是以任務分析法開展家庭治療四步模式的理念為治療師從事家庭治療時的具體任務，試圖了解治療師在四步模式理念下如何實際介入、及案家在會談過程中所出現象徵任務有效的行為特徵。研究參與者為自願前來的5個家庭，由研究者自行擔任治療師， 對家庭提供5到9次的家庭治療。研究方法依任務分析法之步驟，先整理出四步模式的理念任務，接著蒐集實際治療行為的資料文本，輔以對案家的訪談，以質性取向之內容分析法比對理念任務與實際治療行為。研究結果開展出13項進行四步模式時的治療師任務、43項象徵任務有效的案家改變特微，並對任務間的動態關係進行探討。研究結論包括：1.使用探索性語言有助於在治療中推展四步模式理念；2.使用介入型治療技巧有助於步驟二和步驟三對家庭深層訊息的探索；3.案家在步驟四中的改變挑戰治療師對完美家庭的迷思。研究者根據研究結果反思何謂家庭治療的終點行為、及主訴問題對治療歷程的影響，並對家庭治療實務工作、訓練及未來研究提出建議。

In this study, task analysis was applied to the four-step model of family therapy to understand how family therapists intervened and the behavioral characteristics clients showed during the consulting process. Five families volunteered as research participants. Researcher of this study was also the family therapist who provided between five to nine therapy sessions to the respective families. Task analysis was applied to delineate the four-step conceptual tasks, followed by collecting transcripts based on actual therapeutic behaviors in counseling sessions. Content analysis was used to compare the conceptual tasks and actual therapeutic behaviors. Results revealed 13 therapist tasks related to the four-step model, 43 task characteristics that indicated effective change, and interactive relationships related to therapeutic tasks. This study concludes that: 1. Exploratory language in the therapeutic process is helpful to implement the four-step conceptual model; 2 Interventionist skills in step 2 and step 3 can promote more in-depth exploration of family messages; 3. Client changes in step 4 challenged therapist's myth of what constituted a perfect family. Based on the results, researcher reflected on what the ultimate behaviors of family therapy is and how client problems affect the therapeutic process. Suggestions for family therapeutic tasks, training, and future research were offered.