生源质量是高等教育人才培养质量的起点，理解生源质量对于建设一流本科教育具有重要意义。本研究借助“国家大学生学情调查研究数据库（NCSS）”2011—2020级大一学生的调查数据，考察十年来我国高校本科生源质量的特征，进一步探索规模扩张对不同类型高校生源质量的影响效应。研究结论如下：首先，近十年来规模扩张使得更多学生进入本科院校，因此生源自评的高中成绩位次相对有所下滑，但能力呈波动上升趋势；专业适切性保持高位稳定，学校适切性也呈波动上升趋势；公平性总体较为稳定但多元性不足。其次，应用型高校在规模扩张中承担了更大的责任，与研究型高校相比，面临生源自评高中成绩位次下滑更大、学校和专业适切性不足、生源多元性不足等多重挑战；而研究型高校应当更加关注生源的公平性。建议生源质量研究从比较目的转向认识目的，以帮助高校基于生源质量改善教育教学，实现大学生增值发展；同时建议为应用型高校发展提供一定的政策和资源支持，以覆盖更大范围的本科生，建设更广泛意义上的一流本科教育。

The quality of undergraduate enrollment is the starting point of higher education quality. During the transition from mass to universal higher education, understanding the quality of undergraduate enrollment is of great significance for improving the teaching quality of colleges and universities and building first-class undergraduate education. Based on the data of NCSS, this study evaluates the characteristics of undergraduate enrollment quality, and further explores the impact of higher education expansion on undergraduate enrollment. The results show that, firstly, although the students’ achievements decline, their abilities increase; the profession and university’s suitability show an upward trend; fairness is generally stable but lacks diversity. Secondly, the applied universities have assumed greater responsibility in the expansion, facing multiple challenges, such as a large decline in the students’ scores, insufficient profession and university’s suitability, and insufficient diversity of students. And the research universities should pay more attention to the fairness. The research suggests that the research on quality of undergraduate enrollment should be shifted from the comparative purpose to the cognitive purpose, so as to help colleges and universities improve education and teaching based on the quality of student resources and realize the value-added development of college students. And it is suggested to provide certain policy and resource support for the development of applied universities, so as to cover a wider range of undergraduate students and build a more extensive sense of first-class undergraduate education.