The undergraduate admission system of world-class universities is an important guarantee for selecting outstanding talents，promoting the development of disciplines and improving the quality of higher education.The undergraduate admission systems of the six world-class universities in the United States，Britain，Germany and Japan etc.have their own characteristics due to their different political，economic and cultural conditions.Meanwhile，there are also many common features in the design of the systems for selecting outstanding freshmen，including multiple channels for admission，diversified selection methods，comprehensive evaluation system，and autonomy in enrollment.At present，there is an urgent need to optimize the undergraduate admission system for the construction of world-class universities in China and for the new round of comprehensive reform of college entrance examination.The undergraduate admission systems of the six world-class universities could be of reference for China in solving its problems in the diversified reform of college entrance examination and in optimizing the undergraduate admission system of its world- class universities.Firstly，efforts should be made to deepen the reform of comprehensive evaluation of college entrance examination.The second is to make the diversified reform of the college entrance examination more scientific.Thirdly ，attention should be paid to the educational function of the college entrance examination system.The fourth is to further expand the enrollment autonomy of colleges and universities.