Based on the theory of sustainable development education, this paper tested the adaptability of contemporary university freshmen. Using the compilation and revision of China’s College Student Adjustment Scale (CCSAS). This paper examines five dimensions: personal emotional adaptability, learning adaptability, interpersonal adaptability, university identity, and living adaptability. Using a sample of 640 freshmen (from more than 30 universities) and considering the three dimensions of gender, major, and origin, the paper reaches the following conclusions. Generally, the adaptability of freshmen was positive and their adaptation is good; from the perspective of gender, males and females are different in physiology and psychology; from the perspective of major, there are no significant differences; from the perspective of students’ origin, there was no significant difference in general, but there were significant differences in personal emotions and university identity. Based on the above results, this paper emphasizes that to achieve the goal of sustainable development education, universities should begin to pay attention to the adaptability of students as soon as they enter the university. In addition to paying attention to the quality of teaching and learning, universities should also pay attention to the individual differences among students and the related factors that hinder their sustainable development. To ensure that students can meet the challenges of society in the future, the university should cultivate students’ awareness of sustainable development and their ability to participate in and develop sustainable practices.