Objective To analyze the volatile oil from the branches of Picrasma quassioides. Methods Volatile oil was extracted from the branches of P. quassioides by steam distillation. GC-MS method was used to analyze the components. Results A total of 49 compounds were isolated, and 46 compounds were successfully identified, which represented over 98% of the total oil composition. The major components of the volatile oil in the branches of P. quassioides included caryophyllene (12.83%), 12-oxabicyclo[9.1.0]dodeca-3,7-diene,1,5,5,8-tetramethyl-[1R-(1R*,3E,7E,11-R*)] (12.29%), 1-hexanol (9.96%), naphthalene, 1,2,3,5,6,7,8,8a-octahydro-1,8a-dimethyl-7-(1-methyletheyl)-[1S-(1a,7a,8aa)] (7.32%), aromadendrene oxide-(2) (6.69%), and α-caryophyllene (3.88%). Conclusion The major components in volatile oil are terpenoids, hydroxy compounds, and other acyclic alkane compounds.