Abstract: OBJECTIVE To establish a rapid method for qualitative determination of 14 chemical drugs(including voglibose, acarbose, vildagliptin, chlorpropamide, acetohexamide, sitagliptin, tolazamide, dapagliflozin, nateglinide, muraglitazar, canagliflozin, troglitazone, GW501516, ciglitazone) illegally added into antidiabetic traditional Chinese medicines by LC-MS. METHODS Samples were separated on a SHISEIDO HPLC CAPCELL-PAK C₁₈ column(4.6 mm×150 mm, 5 μm) after ultrasonic extracted by methanol with the mobile phase consisted of methanol-0.01 mol·L^-1 ammonium acetate solution by gradient elution. The flow rate was 0.5 mL·min^-1. Ion trap mass spectrometry(ITMS), electrospay ionization source(ESI) and positive and negative ion scanning were adopted to analyze 14 antidiabetic chemicals with full scan MS and full scan MS² modes. The qualitative analysis of 14 antidiabetic chemical drugs was performed by comparing the chromatograms and mass spectrograms of the reference substances and samples. RESULTS The 14 compounds were well separated under the selected LC-MS condition. The limits of detection were all in the range of 0.05-3.5 mg·kg^-1. Out of 30 batches of samples, 3 samples contained canagliflozin and 1 sample contained nateglinide. CONCLUSION The method is simple, sensitive and rapid in the detection of chemical drugs illegally added into antidiabetic traditional Chinese medicines.