A method of simultaneous determination of the eleven phenol and aniline dyes in oxidative hair dyes by ultrasonic-assisted extraction and high performance liquid chromatography-tandem mass spectrometry was developed. The orthogonal and single-factor experiments were designed to and optimize the ultrasonic-assisted extraction conditions, and the samples were extracted using 10 mL of 5% methanol under the conditions of ascorbic acid as an antioxidant for 10 min. The gradient elution program and the electrospray ionization mode change were together used for the optimization of the measurements, and the determinations were completed by using the multi-reaction monitoring scan. The detection limits were 1. 15-9. 43 μg/g, the recoveries of spiked samples were 88. 0%-118. 1%. The method can be used to determine trace prohibited and restricted dyes in hair dyes.