Objective@#To investigate the association of ambient fine particulate matters (PM2.5) exposure with anxiety in middle-aged and elderly people in China.@*Methods@#Using a stratified random sampling method, 5 997 middle-aged and elderly people (aged 40-89) who resided in the region for more than 2 years and had no hearing or language impairment were selected from 32 districts/counties in the key areas for air pollution prevention and control in China from October 10th, 2017 to February 7th, 2018. Information about demographic characteristics, socioeconomic factors and health status were collected by questionnaire survey and physical examination. The anxiety symptoms were assessed by 7-item Generalized Anxiety Disorder Scales. Three-year moving average concentrations of PM2.5 were calculated to estimate exposure level. The multivariate logistic regression model was conducted to assess the association between PM2.5 exposure and anxiety. The interaction of age, gender, overweight, education, smoking, drinking and chronic diseases was also analyzed by likelihood ratio test.@*Results@#There were 2 995 (49.94%) males subjects, 4 092 (68.23%) subjects with education of secondary school or above and 2 576 (42.95%) subjects with self-reported chronic diseases among the 5 997 middle-aged and elder participants. The prevalence of anxiety was 6.64% (n=398). The mean±SD of 3-year moving average concentrations of PM2.5, O3 and SO2 were (53.50±13.38), (90.58±13.26) and (40.29±12.56) μg/m3, respectively. PM2.5 had significantly association with anxiety, and the corresponding OR value was 1.17 (95%CI: 1.05,1.31) with a 10 μg/m3 increment of 3-year moving average concentrations of PM2.5. Compared with female (OR (95%CI)=1.07 (0.93,1.23)), those with no chronic diseases (OR (95%CI)=1.06 (0.93,1.20)) and those with primary school degree or below (OR (95% CI)=0.90 (0.75,1.09)), the association between PM2.5 and anxiety was stronger among male (OR (95%CI)=1.35 (1.12,1.63)) and those with chronic diseases (OR (95%CI)=1.77 (1.31,2.38)), middle school education (OR (95%CI)=1.43 (1.22,1.67)), college education and above (OR (95%CI)=1.68 (1.05, 2.67)), all the P interaction values were <0.05.@*Conclusion@#PM2.5 exposure has significantly positive association with anxiety. The associations are stronger in male, people with higher educational qualifications and patients with chronic diseases.