Abstract: The determination of methanol solvent residues in the samples of nitazoxanide using gas chromatography-selected ion monitoring-mass spectrometry(GC-SIM-MS)has been curried out. A peak area standard curve method is used as the quantitative method. The heating temperature of the sample was 70 ℃, with an equilibrium time of 20 min, SIM m/z 32, m/z 31, 30, and 29. The concentration of toluene was linear in the range of 0.5~100 μg /mL (R²=0.999 92). The relative standard deviation of the method was 2.49%~4.85%, the recovery was between 94.5%~102.8%, the detection limit was 0.5 μg/mL, which were in accordance with the requirement of quantitative analysis.