The successful adjustment of international students to the new environment depends on their ability to interact effectively with the external environment. However, the literature has not yet provided a clear understanding of how the support provided by host universities affects the academic achievement and cultural adaptation of international students, particularly in longitudinal studies involving students from different countries and regions in China. Based on Student-centered Learning Engagement framework, this study developed and tested a model composed of three variables—university support, academic achievement and cultural adaptation, and collected data from South Asian students at Chinese universities from 2017 to 2019 through questionnaires. The findings revealed that university support significantly affected cultural adaptation through academic achievement. The study suggests that Chinese universities should provide appropriate levels of support for international students to achieve positive academic outcomes, and to better understand and adapt to the universities, societies, and cultures.