Abstract: GC-MS/MS was applied to the determination of barbiturate drugs, i.e., barbital, amobarbital, secobarbital and phenobarbital, in blood. The sample was extracted with a mixture of ethyl acetate and cyclohenane (1+1) by accelerated solvent extraction, and the extract was evaporated to dryness by N2-blowing and dissolved with 1.0 mL of methanol. VF-5MS chromatrographic column was used for separation, and the multi-reactions monitoring with electron impact ionization source was adopted in MS. Linear relationships between values of peak area and mass concentration of the 4 barbiturate drugs were kept in the same range of 10-1 000 μg·L-1, with detection limits (3S/N) in the range of 0.07-0.26 μg·L-1. On the base of blank blood sample, test for recovery was made by standard addition method, values of recovery found were in the range of 77.8%-93.4%, with RSD′s (n=7) in the range of 2.3%-6.9%.