Objective To establish a HPLC-MS/MS method for the determination of melatonin in human saliva.Methods Sabra samples and internal standard(itopride)were extracted by dichloromethane after alkalization.The analysis was conducted using a Sunfire C18 column with gradient elution and the column temperature iS 35 ℃.The mobile phase consisted of methanol and water with 0.1%formic acid at flow rate of 0.3 mL·min~(-1).Analysis in mass Was operated by the electrospray ionization.Results LLOQ of the method is 5.48 pg·mL~(-1)(S/N ＞10).The standard curve is linear in the range of 5.48～250.00 pg·mL~(-1)(γ2=0.9994).LLOD is 2 pg·mL~(-1)(S/N＞3).The RSDs of interday and intra-day are all less than 15%.The extraction recovery is closed to 60%.Conclusion The method is fast,precise and sensitive,and suitable for the determination of melatonin in human saliva.