To establish a method for determination of perchlorate and chlorate in drinks by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) based on isotopic internal standard method. The perchlorate and chlorate residue in liquid drinks were extracted with methanol, in solid drinks with acetic acid solution, then centrifuged. The supernatant was cleaned-up with PSA/C18 cleanup tube. The separation of perchlorate and chlorate was carried out on a Acquity CSH fluorophenyl column(100 mm×2.1mm, 1.7 μm) and the detection was performed with tandem mass spectrometry with internal standard method for quantification. The peak area ratio of perchlorate and chlorate had a good linear relationship with their mass concentration within their respective linear ranges, with correlation coefficients(r) greater than 0.999. The limits of detection of perchlorate and chlorate were 0.2and 1 μg/L respectively and the limits of quantification were 0.5 and 3 μg/L respectively. The mean recoveries of two compounds were from 84.0% to 105.5% with relative standard deviations from 4.2% to 17.0% and 82.7% to 112.1% with relative standard deviations from 5.5% to 18.4%(n=6), respectively. The perchlorates in 11 kinds of beverage samples were 0.53-4.12 μg/L, chlorates were 3.27-61.86 μg/L. This method is simple, sensitive, accurate and reliable, which is suitable for the determination of perchlorate and chlorate in drinks.