Abstract: 【Objective】Elucidating the chemical composition and antibacterial activity of volatile oils from the leaves and fruits of Callistemon viminalis could provide a theoretical basis for the comprehensive development and utilization of C. viminalis. 【Method】Hydro-distillation was used to extract volatile oils from leaves and fruits and their chemical compositions were analyzed by gas chromatography-mass spectrometry(GC-MS). Furthermore, the filter paper diffusion method was used to detect the inhibitory activity of these oils against seven bacterial species. 【Result】The yields of volatile oils from the leaves and fruits of C. viminalis were 0.87% and 0.16%(based on fresh weight), respectively. GC-MS analysis identified 14 components in the volatile oil of leaves and 17 components in that of fruits, which accounted for 93.34% and 90.29%, respectively, of the total volatile oil contents of the two tested samples. Eucalyptol(52.89%),(1R)-(+)-α-pinene(17.28%)and(-)-α-terpineol(10.70%)were the major compounds in the volatile oil of leaves, whereas eucalyptol(38.53%),(1R)-(+)-α-pinene(29.90%)and α-bornene(8.02%)were the major compounds in that of fruits. The fruit volatile oil showed strongest inhibitory activity against Agrobacterium tumefaciens, with an inhibition zone diameter of(25.2±2.8)mm. In contrast, the volatile oil from leaves showed strongest inhibitory activity against Ralstonia solanacearum, with an inhibition zone diameter of(22.3±1.5)mm. 【Conclusion】The percentage composition of volatile oil in the leaves of C. viminalis was higher than that in the fruits. Eucalyptol and(1R)-(+)-α-pinene were the main volatile oil components in both leaves and fruits. The volatile oil extracted from fruits showed better antibacterial activity against bacteria than the volatile oil extracted from leaves.