Monodisciplinarization is an unusual but reasonable growth strategy for multidisciplinary organizations in China's univer-sities,as can be seen in this case study of the Earth System Science(ESS)Research Institute of University A,which has trans-formed itself from a multidisciplinary organization into a monodisciplinary one.Under great pressure of legitimacy building and effi-ciency improvement,the ESS Research Institute,or the subject of this case study,has been pushed toward institutional convergence rather than divergence.In order to earn academic recognition and social acceptance,as well as reduce costs and minimize time wast-ing for institutional development,the ESS Research Institute has no choice but align itself with the national policies and regulations that still favor monodisciplinarity over multidisciplinarity.From the perspective of organizational institutionalism,monodiscipli-narization is in fact(often reluctant)strategic adaptation that helps multidisciplinary organizations make a breakthrough and achieve institutional growth.