我國自1996年起開始試辦綜合高中，迄今已有十餘年。試辦綜合高中的目的在於促使我國後期中等教育能在高中、高職之外，提供另一條不同的選擇進路，俾使學生得以適性發展，學得多方面的知識，達到適性教育的目標。過去國內關於綜合高中分流政策的研究，大都集中在探討綜合高中的辦學績效和實施困難，而非該政策對學生學習成就的影響之探討。有鑑於此，本研究進一步探討：（1）哪些因素會影響國中畢業生選擇就讀普通高中和綜合高中學術導向組；（2）就讀綜合高中的學生，其學生學習成就是否優於就讀一般高中或高職；（3）綜合高中的課程分流政策是否能減少教育階層化的產生。 原始資料取自臺灣教育長期追蹤資料庫（Taiwan Education Panel Survey）公開使用版中的第一波到第四波國中追蹤樣本資料，並使用傾向分數配對法（Propensity Score Matching）探討上述三個研究目的。研究結果發現：(1)控制其它相關因素之後，過去學習成就和家庭社經背景愈佳者，愈有可能就讀普通高中及綜合高中學術導向組；(2)在學生學習成就表現上，就讀綜合高中的學生並不比就讀一般高中或高職的學生來得好；(3)綜合高中分流政策和制度性分流一樣，都會產生教育階層化現象。最後，本研究說明本研究結果對綜合高中分流政策的意涵，及提出研究建議供後續研究之用。 / Since 1996, Taiwan government launched the policy of Comprehensive High School (CHS) to relax the traditional system of curriculum tracking at the level of the senior secondary education. A number of studies and on-site evaluation reports on CHS have been made. So far, these studies and reports focused on exploring the performance of comprehensive high schools and difficulties in implementation of the policy. No evaluation of the impacts of the CHS policy on student achievement has yet been done. The purpose of this study is to examine the effects of the CHS policy on students’ achievement in the upper secondary education in Taiwan. This study attempts to answer the following research questions: (1) What factors influence junior-high school graduates’ decision on attending general high schools, and the academic track in comprehensive high schools? (2) Do students enrolling in comprehensive high schools perform better academically than those enrolling in general or vocational high schools? (3) Do curriculum tracking in comprehensive high schools enhance or reduce inequality in educational achievement? Using the data from the public released core panel data of the Taiwan Education Panel Survey (TEPS) in 2001, 2003, 2005, and 2007, this study employs the method of propensity score matching (PSM) to estimate the average treatment effect of CHS policy on student achievement. All results of PSM analysis indicate that (1) all else being equal, students with higher prior student achievement and better socio-economic backgrounds have more opportunities to enroll in an academic track, including senior high schools and the academic track in comprehensive high schools, than those with lower level of prior achievement or socio-economic backgrounds; (2) for those enrolled in comprehensive high schools, there is virtually no gain in student achievement from the CHS policy; and (3) tracking in comprehensive high schools produce inequality in educational achievement, which is similar to tracking between general and vocational high schools. Finally, the present study discusses the implications of the CHS policy and suggests directions for future research.