A simple and rapid magnetic solid-phase extraction (MSPE) method using PEGylated multi-walled carbon nanotubes magnetic nanoparticles (PEG-MWCNTs-MNP) as absorbents is proposed for isolation and enrichment of aflatoxin B (AFB), aflatoxin B (AFB), aflatoxin G (AFG), aflatoxin G (AFG), aflatoxin M (AFM), aflatoxin M (AFM), ochratoxin A (OTA), zearalenone (ZEA), zearalanone (ZAN), α-zeralanol (α-ZAL), β-zeralanol (β-ZAL), α-zeralenol (α-ZOL), and β-zeralenol (β-ZOL) from liquid milk. Combined with ultra-high performance liquid chromatography Q-Exactive high resolution mass spectrometry, simultaneous qualification of these mycotoxins was achieved with sensitivity and specificity. The proposed method showed a good linearity (R ≥ 0.995), high sensitivity (limit of detection in the range of 0.005-0.050 μg/kg and limit of quantification in the range of 0.015-0.150 μg/kg), adequate recovery (81.8-106.4%), and good repeatability (intra-day precision in the range of 2.1-8.5% and inter-day precision in the range of 3.9-11.7%). It has been successfully applied to the determination of 13 mycotoxins in real liquid milk samples.