Supercritical CO2 extraction method was applied to essential oil from Thuja sutchuenensis in the present study. The composition of the essential oil was identified by GC-MS. The extraction conditions were optimized by orthogonal tests. Results: The main factors influencing the extraction yield are extraction pressure, extraction temperature and extraction dynamic time. The Optimization of process: filling coefficient was 0.68, the extraction pressure and temperature were 20 MPa and 50 ℃, dynamic time was 60 min and static time was 30 min. The essential oil extraction rate were 7.20%～7.31% under this condition. 28 components were identified in the Thuja sutchuenensis, primarily terpene compounds containing Thujopsene，α-cedrol and cuparene, accounting for 45.5%, 25.41% and 7.11%, respectively.