Objective To investigate the mixed placement of medical waste and domestic waste in public area of a large tertiary first-class general hospital. Methods A random questionnaire survey was carried out among patients and their accompanying persons in the public area of medical institutions, mixing placement of medical waste and domestic waste in medical waste bins and domestic waste bins in the public area of medical institutions were checked and recorded. Results A total of 100 questionnaires were distributed, 96 of which were available and 85.42% (82/96) of respondents received at least junior high school education. According to the questionnaire survey, 59.38% of respondents knew that hospital waste were divided into medical waste and domestic waste, 33.33% knew the color of medical waste bin and packaging bag that medical waste and domestic waste should be put into respectively, 29.17% knew that medical waste could be reused after harmless treatment, 77.08% thought that classfied disposal logo of medical waste and domestic waste in their hospitals was not obvious, 9.38% had received education on classified disposal of medical waste and domestic waste, 65.63% were willing to take the initiative to implement classified disposal of medical waste and domestic waste in the future medical treatment process. Through on-site inspection of mixed placement of medical waste and domestic waste in medical waste bins and domestic waste bins in public area, it was found that 41.18% of domestic waste bins were mixed with medical waste, and 83.33% of medical waste bins were mixed with domestic waste. Conclusion The mixed placement of medical waste and domestic waste in public area of medical institutions is serious, it is necessary to implement targeted comprehensive interventions to further guide the classification of medical waste and domestic waste in public area of medical institutions.