Abstract: GC-MS was used for the determination of nicotine in rat plasma. The plasma sample was purified by a protein precipitation method and then separated on a DB-Wax capillary column. EI and SIM were adopted in MS. Anethole was used as the internal standard for quantification. Pharmacokinetic parameters were calculated by using software PKSlover 2.0. The linearity range of nicotine was 0.10-2.0 mg·L-1 with detection limit of 4.59 μg·L-1．The recovery rates measured by standard addition method were in the range of 85.0%-90.1% with RSD less than 3.0%. The method was applied for pharmacokinetic study of nicotine in the rat plasma samples. AUC0-t,AUC0-∞,Tmax and ρmax were 8. 570 mg·L-1·h-1,10.49 mg·L-1·h-1,1.0 h,and 998.9 μg·L-1,respectively,displaying a pharmacokinetic process.