A stage of academic adaptation is inevitable for freshmen when they come to the university. The latest reform of the National College Entrance Examination (NCEE) and the Major Category Enrollment scheme (MCES) may change freshmen’s satisfaction with their first-choice major, and affect their academic adaptability. All these issues deserve our exploration and study. Under the influence of the new NCEE and the MCES, the academic adaptation of first-class university undergraduates is generally good. There is no significant difference in undergraduates’ first-choice major satisfaction and academic adaptation between new NCEE candidates and traditional NCEE candidates. However, many undergraduates majored in science, engineering, agriculture and medicine are of academic maladjustment and low satisfaction with their first-choice majors. Under the MCES, undergraduates’ first-choice major satisfaction has a significant positive impact on their academic performance. Learning motivation and learning strategies play a chain mediating role in the process. Therefore, first-class universities should improve their major selection mechanism, improve undergraduates’ understanding of disciplines and majors, promote undergraduates’ satisfaction with their first-choice majors, and guide them to set learning objectives and develop effective learning strategies, so that they can get through the adaptation period smoothly.