The present invention relates to a diagnosis method of liver cancer using mass spectrometry of α-fetoprotein derived glycopeptide. Particularly, according to the AFP glycopeptide analysis method of the invention, fucosylation rate of the glycopeptide having the sequence composed of Val-Asn-Phe-Thr-Glu-Ile-Gln-Lys is analyzed to diagnose liver cancer in the early developmental grade. In particular, fucosylation rate is higher in the liver cancer patients than in other liver disease patients, so that the comparison of the fucosylation rate can be useful to diagnose or distinguish liver cancer from other liver diseases in the early HCC patients.