To investigate the current situation and related factors of adults environmental health knowledge-attitude-practice(KAP)in four cities. From March to April 2021, 1252 permanent residents in Mianyang City, Ya'an City in Sichuan Province, Suzhou City and Yangzhou City in Jiangsu Province were investigated on environmental health KAP by using a self-made electronic questionnaire. Analysis of variance, multiple linear regression and Person rank correlation were used to analyze the difference of public environmental KAP level, related factors, and the correlation of knowledge, attitude and behavior scores. There were significant differences in the level of environmental health KAP among people in different cities(F=47.632, P<0.001), age group(F=34.676, P<0.001), education level(F=49.574, P<0.001), BMI(F=4.560, P=0.003), total annual family income(F=27.977, P<0.001), smoking status(t=11.121, P=0.001)and ways of ingesting environmental health knowledge(F=88.405, P<0.001), and except BMI, other items were the related factors of environmental health KAP. The score of environmental health attitude was higher than that of behavior and knowledge(F=154.34, P<0.001). The scores of knowledge and behavior, knowledge and attitude, attitude and behavior were correlated, and the correlation coefficients were 0.667, 0.414 and 0.450 respectively(P<0.01). The number of ways to acquire environmental health knowledge, total annual family income, education level, age and smoking status are all related factors of the adults environmental knowledge-attitude-practice level in four cities in 2021.