Abstract: The dendrobium candidum sample soaked with appropriate amount water was extracted ultrasonically with acetonitrile accompanied by high speed vortex. After centrifugation, the supernatant was purified with dispersive solid phase extraction. C₁₈ and PSA were used as adsorbents. GC-MS/MS was applied to the determination of residual amounts of 41 pesticides in purified liquid with dispersive solid phase extraction. Agilent VF-5MS chromatographic column was used for GC separation and the multiple reaction monitoring mode was adopted in MS/MS determination. cis-Heptachlor epoxide was used as internal standard. Detection limits (3S/N) of the 41 pesticides were in the range of 0.001-0.024 mg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 75.1%-115%, with RSDs (n=6) of determined values in the range of 0.40%-11%.