This study aimed to measure the knowledge and perceptions of medical, public health, and nursing students about climate change and its impacts, and to identify associations between the knowledge and perceptions. Data were from a nationwide cross-sectional survey of 1387 students sampled in five different regional universities in China (April–May 2017). The knowledge and perceptions of the participants were collected by self-administered questionnaires. We found that most respondents believed that climate change is generally “bad” (83%) and bad for human health (88%), while 67% believed that climate change is controllable. The vast majority of respondents acknowledged illness conditions resulting from poor air quality (95%), heat stress (93%), and extreme weather events (91%) as potential impacts of climate change. Nevertheless, only 39% recognized malnutrition as a consequence of food deprivation resulting from climate change. Around 58% of respondents could correctly identify the causes of climate change. The knowledge of the causes of climate change was not associated with the ability to recognize the health consequences of climate change. However, the knowledge of causes of climate change was a significant predictor of increased awareness of the negative impacts of climate change between the medical and nursing students, although this was not the case among their public health counterparts. Poor knowledge about the causes of climate change is evident among students in China. They are able to recognize the direct links between weather events and health, but less likely to understand the consequences involving complicated pathways. Research and training into the underlying mechanisms of health impacts of climate change needs to be strengthened.