Abstract: The chemical constituents of fatty acid in the roots of Caragana sinica were determined and identified by GC/MS. Eighteen compounds were identified. The main components are 9,12,15-octadecatrienoic acid (28.41%), 9,12-octadecatrienoic acid (34.61%), Hexadecanoic acid (19.33%) and octadecatrienoic acid (6.37%).