A magnetic graphene composite was prepared and characterized by transmission electron microscopy and fourier transform infrared spectroscopy. A novel method was developed for the simultaneous determination of 5 phenoxy acid herbicides in camellia oil by magnetic solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry, which using magnetic graphene composite for enrichment and clean-up. The analysis time and cost of this method were relatively decreased by use of magnetic graphene in the detection of phenoxy acid herbicides in camellia oil, it also increased the efficiency of adsorption and elution of the target compounds. The result showed a good linear correlation with the coefficients greater than 0.999 68 when the 5 phenoxy acid herbicides within the range from 0.01 to 0.20 mg/kg; the average recovery rate was from 88.1% to 95.0% with the relative standard deviation (RSD) ranged from 2.6% to 7.3% when these 5 targets on the levels of 0.02, 0.05, 0.10 mg/kg, which totally meet the testing needs of the 5 phenoxy acid pesticides in camellia oil.