本文首先以台大新生集中於明星高中程?的高低為指標，探討考試分發入學相較於多元入學的其他管道，是否比較?會受到考生家庭背景的影響？結果發現，台大學生集中於明星高中的程?以大學?招時期最高，其次依序是推甄入學、指考分發、繁星推薦。本文接著以中低收入戶學生占整體學生人?的比??比較台大、哈佛大學、加州大學柏克萊分校所提供的垂直社會?動機會，結果發現，台大所提供的垂直社會?動機會最低，哈佛大學次之，加州大學柏克萊分校最高。本文同時整?相關文獻和文件的內容，探討造成此一現象的政策背景與大學入學標準變革的影響。 This paper uses the concentration level of National Taiwan University (hereafter NTU) freshmen from star high schools as an indicator for the influence of social economic status on the possibility of matriculation into NTU among different channels of the Multiple Entrance System for Colleges. The concentration level from star high schools was found to be the highest during the united entrance examination era, followed by admission by school recommendation and admission by application, the joint college assigned-subject examination, and the stars project. This paper then uses the ratio of undergraduates from low-income families as an indicator for the opportunity of vertical social mobility provided by a prestigious university. The opportunity of vertical social mobility was found to be the highest at U.C. Berkeley, followed by Harvard and NTU. The rest of this paper conducts a documentary research to investigate the policy background and changes in college admission standards that have led to this divergence in the opportunity for social mobility.