Abstract: Atmospheric background monitoring is a long-term and fixed-point observation of atmospheric components that are fully mixed and free from local pollution in areas without human activities, reflecting the variation characteristics of atmospheric composition on global or regional scales. The long-term, continuous, and effective monitoring data of atmospheric composition and its variation characteristics obtained by China atmospheric background stations provide support for diplomatic negotiations on climate change, prevention and control of atmospheric pollution and scientific research. In this paper, 7 atmospheric background stations of China Meteorological Administration are briefly introduced, with emphasis on the analysis of the concentration trends and influencing factors of the background station observation elements-CO₂, CH₄, O₃ and CO by using the method of comparison and statistical analysis as well as HYSPLIT backward trajectory model. The result shows significant increasing trend of CO₂ concentration in each station, similar to that in the Mauna Loa station and with a seasonal variation characterized by high concentration in winter and spring, low concentration in summer and autumn. In addition, the concentration of CH₄ in each station shows a clear upward trend and is higher than that in the Mauna Loa station, and the change of CH₄ concentration is closely related to its photochemical reaction and local source emission. The O₃ concentration is featured with a seasonal variation, high in winter and spring, and low in summer. The CO concentration shows a decreasing trend, which is related to the external conditions such as human activities and CO atmospheric reaction. Therefore, the variation trend of observation elements of atmospheric background stations is affected by local climate conditions, monsoon transport, atmospheric boundary layer and other environmental conditions. It is also closely related to the regional environmental emissions in eastern developed area.