Abstract: OBJECTIVE To establish a UPLC/Q-TOF-MS method for the detection of illegally added chemical diclofenac in health care products. METHODS The samples were separated by Phenomenex C₁₈ column, mobile phase was 0.02 mol·L^-1 ammonium acetate solution-acetonitrile with the gradient elution. TOF and target MS/MS scanning mode was adopted. RESULTS Confirmed by standard, diclofenac were detected in sample, the compounds in slimming health foods had not been reported. CONCLUSION The method can be used for rapid identification diclofenac illegally added in slimming health care products.