Abstract: Serum sample was made alkaline by sodium hydroxide,and then was added to minicolumn.Levo-dropropizine was eluted with methylene dichloride.The eluted organic phase was dried under nitrogen.The residue was derived by BSTFA before analyzed by Tandem GC-MS.The parention was m/z 175,and daughter ion was from m/z 50 to m/z 200.The external standard method was used for quantitative.The liner range,the correlation coefficient,the detection limit,the recoveries and RSD was 0.005~4.0 μg/mL,0.99,0.005 mg/L,80%~102.5%,1.67%~4.00%,respectively.