LC-Q-TOF/MS was used to detect five illegal additives (rotundine, sinomenine, venlafaxine, melatonin, zaleplon) in sedative health food. The five illegal additives were extracted by ultrasound with a mixture of methanol and ammonium acetate 20 mmol/L. A gradient system of a mixture of 0.1% formic acid with multi-reaction monitoring (MRM) was employed for quantitative determination at the ion source for ESI source, and the positive ion detection conditions were employed. The time-of-flight mass spectrometer was chosen, and the detecting parameters were set up and optimized. Qualitative and quantitative analysis of 5 kinds of illegal additives were carried out. The results showed that the five illegal additives were in good linear relationship within the range of 10～1 000 μg/L and the correlation coefficient was greater than 0.99. The average recovery of the blank sample was between 92.8%～110.1%, and the precision was 0.9%～1.8%. Six kinds of commercially sold Sedative health food samples (A,B,C,D,E,F) were extracted by methanol and analyzed by LC-Q-TOF/MS. The results showed that a kind of capsule sample D contained sinomenine which content was 1.656 mg/kg. Therefore, the method had the advantages of strong selectivity, high sensitivity, quick detection.