Abstract: To systematically analyze the chemical component characteristics and primary sources of atmospheric PM_2.5 in northern coastal city, this study selected Qingdao city as the research object, collected ambient PM_2.5 samples in Laoshan District, Qingdao City from March 2021 to February 2022, and determined water-soluble inorganic ions, carbon components, and chemical elements, and analyzed the chemical component characteristics of atmospheric PM_2.5. Positive matrix factorization (PMF) and potential source contribution function (PSCF) were utilized to analyze the main contribution sources and potential source areas of ambient PM_2.5 in Qingdao City. The results showed that: (1) The average concentration of PM_2.5 during the sampling period was 42.2 µg/m³. NO₃^-, NH₄⁺, SO₄^2-, and OC were the dominant components in PM_2.5, and their concentrations were 11.77, 5.76, 5.20, and 6.67 µg/m³, accounting for 27.88%, 13.65%, 12.32% and 15.80% of PM_2.5 mass concentrations, respectively. (2) The seasonal variations in the concentrations of each component were commonly consistent with the changes in PM_2.5 concentrations, showing the characteristics of highest in winter, lowest in summer, and little difference in spring and autumn. (3) PMF apportioned results showed that secondary inorganic source was the primary source of ambient PM_2.5 in Qingdao City, with a contribution of 42.8%. Secondary organic sources and the mixed source of coal and biomass burning contributed 18.1% and 15.7% to ambient PM_2.5, respectively. The contribution of motor vehicles was 8.8%, while that of sea salt and ships was 6.0%. The contributions of dust source and industrial process source were relatively lower (5.3% and 3.3%, respectively). The contribution of the mixed sources of coal combustion and biomass burning in winter (24.4%) was substantially higher than those in other seasons. The contributions of dust source in spring and autumn were 6.5% and 9.8%, respectively. The contributions of secondary organic source (23.1%), the mixed source of sea salt and ships (12.4%), and motor vehicles (16.3%) in summer were higher than those in other seasons. (4) The northern part of Jiangsu Province and the central and eastern part of Shandong Province were the main potential source areas for all kinds of sources of ambient PM_2.5 in Qingdao City. The northeast of Jiangsu Province, the Yangtze River Delta and the Yellow Sea were the main potential source areas for the mixed source of sea salt and ships of ambient PM_2.5 in Qingdao City. The results showed that the secondary sources were the main sources of air pollutants in Qingdao City, and the effects of coal and biomass combustion sources, motor vehicle sources, sea salt and ship sources could not be ignored. Secondary sources, motor vehicle sources, sea salt and ship sources might be the key sources of PM_2.5 in northern coastal cities, and their fine management should be strengthened in the formulation of air pollution prevention and control measures.