The leaves and twigs of Juniperus pingii var. wilsonii (Cupressaceae) smell aromatic and are traditionally used as the Tibetan medicine Xuba. Their essential oil obtained by ultrasonic-assisted hydrodistillation and volatiles collected by GC headspace technique were analyzed and compared by GC-MS. The analyses revealed the presence of thirty-nine components in the essential oil, representing 95.8% in content of the total oil, mainly including sabinene (22.6%), elemol (15.5%) and (-)-terpinen-4-ol (9.6%). Thirty-eight components accounting for 99.4% of the headspace volatiles were identified, mainly including sabinene (32.5%), β-pinene (21.9%) and α-thujene (10.3%). The compositions of the oil and headspace volatiles were quite similar, and twenty-five compounds identified were in common, which was 91.3% of the oil and 96.0% of the headspace volatiles in content. The essential oil could obviously inhibit Nitric oxide production in LPS-stimulated RAW 264.7 cells with no significant effect on cell viability, indicating its good anti-inflammatory activity.