OBJECTIVE：To know about the co gnition level and self-medication behavior of antibiotics among urban and rural residents in Lu ’an city of Anhui province ，and to investigate its influential factors and to provide reference for promoting rational use of antibiotics. METHODS ：Totally 684 urban and rural residents aged 18-80 years in Lu ’an city were randomly selected as the research objects by stage sampling method. A self-designed questionnaire was used for household survey ，involving general demographic characteristics ，antibiotics related cognitive level ，antibiotics use behavior and related influential factors ，etc. RESULTS：A total of 657 questionnaires were collected ，with effective rate of 96.1％. Among them ，305 were from urban residents and 352 from rural residents. Among the 657 respondents，38.2％ were male and 61.8％ were female ；their age was （50.30±13.26）years old ；44.7％ of them were educated in primary school or below. 7.8％ of the respondents correctly recognized that antibiotics were not effective to the virus ；12.6％ knew antibiotic resistance ；55.1％ thought that frequent use of antibiotics would reduce the sensitivity of bacteria to it ；23.1％ said they knew the difference between prescription drugs and over-the-counter drugs；58.0％ could tell at least one case of not using antibiotics. For 7 knowledge items ，75.3％ of the residents in the survey area had a total score of less than 3；the cognition level of antibiotics was higher in urban areas and people with higher education level. 66.5％ of the respondents had used antibiotics in the past one year，of which 61.0％ obtained antibiotics by prescription 65161220。E-mail： from doctors ，50.7％ purchased antibiotics by themselves in pharmacies， and 13.1％ used the above two ways both. Among the people who have used antibiotics in the past year ， 81.9％ said they could buy antibiotics without prescription. Among the 657 respondents，49.0％ said that they had to obtain prescription from doctor when taking antibiotics ；68.9％ said that they would stop taking antibiotics when their symptoms improved；19.3％ would increase their dosage in order to enhance the curative effect ；28.3％ would change drugs frequently. Compared with urban residents ，rural residents were more likely to take antibiotics based on prescriptions by physicians [odds ratio （OR）＝1.693，95％ confidence interval （CI）（1.191，2.407）]. The higher the cognitive score ，the lower the behavior rate of having to prescribe antibiotics by doctors [OR ＝0.882，95％CI（0.785，0.991）]，and they were more likely to stop taking antibiotics when symptoms improved [OR ＝1.163，95％CI（1.025，1.319）]，and male were more inclined to increase the dosage of antibiotics to enhance the efficacy [OR ＝1.841，95％CI（1.214，2.792）]. The higher the cognitive score was ，the less likely they were to increase drug dosage to enhance the curative effect [OR ＝0.894，95％CI（0.773，1.034）]，nor were they inclined to change drugs frequently [OR ＝0.873，95％CI（0.767，0.992）]. CONCLUSIONS ：The cognition level to antibiotics of urban and rural residents in Lu ’an city needs to be improved urgently ，and reasonable antibiotic use behavior needs to be standardized. Pure knowledge of antibiotics is not necessarily related to the expected rational drug use behavior. Therefore ，in addition to health promotion for the rational use of drugs for residents ，it is also necessary to create a systematic environment that promotes the rational use of antibiotics and provide residents with multi-channel services for rational use of drugs.