Abstract: Carbon fixation and oxygen release (CFOR) is an important ecological service of the plants. Li-6400 portable photosynthesis test system and Li-2000 plant canopy test system were employed to observe the physiological velocity and leaf area index of 17 widely used afforestation plants in the rural-urban fringe of Chaoyang District, Beijing. The cluster analysis was adopted to classify their CFOR capacities, and the CFOR benefits evaluated quantitatively. The results indicated that the diurnal change curve of net photosynthesis rates of 17 experimental species has one or two peaks. The daily carbon fixation and oxygen release per unit leaf area was respectively 2.92-13.81 g/(m²·d) and 2.12-10.05 g/(m²·d). The daily carbon fixation and oxygen release per unit land area was respectively 11.00-92.71 g/(m²·d)and 8.00-67.42 g/(m²·d). According to cluster analysis results, the CFOR capabilities per unit leaf area of 9 arbors are divided into two levels, 5 shrubs divided into two levels, and 3 herbs divided into two levels. The CFOR capabilities per unit land area of 9 arbors are divided into two levels, 5 shrubs divided into three levels, and 3 herbs divided into two levels. Therefore, in order to enhance the CFOR capabilities of the vegetation system in the rural-urban fringe, not only should the plants which have higher capabilities of CFOR be chosen, but also they should be configured properly through composite model.