The atmospheric PM2.5, total PCDD/Fs-WHO2005-TEQ concentrations, PM2.5-bound total PCDD/Fs-WHO2005-TEQ content, gas-particle partitioning and wet deposition of PCDD/Fs in Jinan and Weihai, from 2015 to 2017, were investigated, respectively. Furthermore, a regression analysis of the air quality index (AQI) and total PCDD/Fs-WHO2005-TEQ concentrations was studied as well. From 2015–2017, the three-year average PM2.5 concentrations in Jinan and Weihai were 76.1 and 32.9 µg m–3, respectively. The three-year average total PCDD/Fs-WHO2005-TEQ concentrations in Jinan and Weihai were 0.0866 and 0.0396 pg-WHO2005-TEQ m–3, respectively, indicating that maritime climate regulation contributes to the spread of pollutants. The three-year average fraction of gas phase total PCDD/Fs-WHO2005-TEQ concentrations in spring, summer, autumn, and winter in Jinan were 26.1%, 63.8%, 30.5% and 4.62%, respectively; while, those in Weihai were 30.7%, 74.5%, 44.4%, and 8.41%, respectively. In 2016, the annual wet deposition fluxes in Jinan and Weihai were 1288 and 483 pg WHO2005-TEQ m–2 year–1, respectively. The annual scavenging ratios of total PCDD/Fs-WHO2005-TEQ were 33080 and 30870 in Jinan and Weihai, respectively. The total concentration of PCDD/Fs-WHO2005-TEQ increased with an increase of AQI and showed a positive correlation; the R2 values of three years (2015, 2016, and 2017) were 0.873, 0.847, and 0.744, respectively. Therefore, knowing the AQI value, the total concentration of PCDD/Fs-WHO2005-TEQ in the ambient air can be roughly estimated using a regression equation.