Abstract：The port area has become a key area of the prevention and control of air pollution in coastal cities because of the large amount emissions of air pollutants and complex sources. To clarify the pollution characteristics and the main emission sources of ambient PM2.5 in the port area， PM2.5 samples were synchronously collected from three port sites and one background site in different seasons in the Qingdao port area in 2019， and their chemical compositions were then determined. The main emission sources and the potential impact areas of these sources were analyzed using positive matrix factorization （PMF） and potential source contribution function （PSCF）， respectively. The results showed that the annual average value of PM2.5 in Qingdao port area in 2019 was 64 μg·m-3， which was 1.8 times higher than the air quality standard in China. Ambient PM2.5 concentration was the highest in Dongjiakou site （74 μg·m-3） and the lowest in Laoshan site （55 μg·m-3）. NO3-， OC， and SO42- were the dominant components of ambient PM2.5， and the proportion of NO3- （13.1%） was substantially higher than those of other components. The concentrations of NO3-， SO42-， OC， and EC at Dongjiakou （13.0， 7.09， 8.98， and 2.91 μg·m-3， respectively） were markedly higher than the other sites， probably indicating that the impacts of coal combustion， industry emissions， especially for iron and steel enterprises， and trucks at Dongjiakou site were more obvious. Meanwhile， the concentrations of these components in winter were substantially higher than other seasons. However， the concentration and proportion of Na were higher in summer （0.96 μg·m-3 and 2.13%）， and the concentrations （1.27 and 0.45 μg·m-3） and proportions （2.79% and 1.00%） of Si and Al in spring were significantly higher than other seasons. PMF results showed that the mixed source of secondary sulfate and secondary organic aerosol （SOA） （the contribution of 22.4%） and secondary nitrate （20.1%） were the main sources of ambient PM2.5 in the Qingdao port area， followed by motor-vehicle （16.7%） and fugitive dust （14.6%）. The contribution of coal combustion was 13.8%， while that of the mixed source of sea salt and ships was 7.2%. The contribution of fugitive dust was high in spring （32.1%）， the contribution of the mixed source of secondary sulfate and secondary organic aerosol （SOA） （31.6%）， and the mixed source of sea salt and ships （19.2%） were high in summer， while those of coal combustion （16.6%）， motor-vehicles （22.8%）， secondary nitrate （23.9%）， steel and related metallurgical sources （3.2%）， and construction dust （3.6%） were high in winter. The central and southern areas of Hebei Province and the central and western areas of Shandong Province were the main potential impact areas of pollution sources of Qingdao port， and the Yellow Sea was the main potential impact area for ship emissions.