Abstract: OBJECTIVE To establish a method for detection of diazepam, estazolam and clozapine illegally added in Shuimianbao capsules by TLC combined with UPLC-MS. METHODS Silica gel(GF₂₅₄) TLC was used, a mixture of ethyl acetate-ethanol-ammonium hydroxide(50∶2∶0.5) as developer, detection under 254 nm. Aglient ZORBAX SB C₁₈ column (100 mm×2.1 mm, 1.8 μm) was used, and the mobile phase consisted of 20 mmol·L^-1 ammonium acetate solution-methanol(50∶50), flow rate was 0.3 mL·min^-1; detection wavelength was 225 nm; column temperature was 35?℃, ESI⁺. RESULTS The diazepam, estazolam and clozapine illegally added in Shuimianbao capsules were displayed obvious dots under 254 nm. Then they were verified by UPLC-MS. CONCLUSION The method is simple and accurate. It can be used for rapid screening and rapid identification of diazepam, estazolam and clozapine illegally added in Shuimianbao capsules.