Abstract: A method for the determination of melamine, cyanuric acid, ammeline and ammelide in dairy product was developed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The samples were extracted by mixed-solvent, some of which were dried by nitrogen. After silylated, melamine and its three analogues were analyzed by GC-MS/MS in the multiple-reaction monitoring(MRM) mode. Good linear relationships are obtained in the concentrations of 0.01—1.0 mg/L of the analyte, while correlation coefficients are 0.999 8, 0.998 2, 0.999 9 and 0.999 8, respectively. The limits of detection are 0.05 mg/kg (S/N=3), and the recovery ranges from 92.5% to 102.5%. This method is simple, rapid and the complex matrix disturbance in dairy product can be avoided when MRM mode is adopted. The method proves to be accurate, reliable, sensitive and suitable for the determination of melamine and its three analogues in dairy product.