Objective:To establish a method for determination of acetonitrile residue in lomerizine hydrochloride. Method: Using head space - GC method. 80% DMF - aqueous solution was used as solution. Sample had been e-quilibrated at 70℃ for 40 minutes. A stainless steel column 2 m long and 3 mm in internal diameter packed with ethylvinylbenzene - divinylbenzene copolymer(diameter from 0. 25 to 0. 32 mm) was used at 130℃ ,FID detector at 250℃. N2 was used as carrier gas at a flow rate of 50 mL · min-1 . Results: Acetonitrile showed good linearity in the range of 23. 46 -234. 6 μg · mL-1 in sample solution. Recovery rate was 96. 7% (RSD =3. 8% ). Detect limit was less than 40 μg · g-1. Conclusion: This method is simple, rapid with good sensitivity. Objective:To establish a method for determination of acetonitrile residue in lomerizine hydrochloride. Method: Using head space - GC method. 80% DMF - aqueous solution was used as solution. Sample had been e-quilibrated at 70℃ for 40 minutes. A stainless steel column 2 m long and 3 mm in internal diameter packed with ethylvinylbenzene - divinylbenzene copolymer(diameter from 0. 25 to 0. 32 mm) was used at 130℃ ,FID detector at 250℃. N2 was used as carrier gas at a flow rate of 50 mL · min-1 . Results: Acetonitrile showed good linearity in the range of 23. 46 -234. 6 μg · mL-1 in sample solution. Recovery rate was 96. 7% (RSD =3. 8% ). Detect limit was less than 40μg ·g-1 . Conclusion: This method is simple, rapid with good sensitivity.