Pancreatic cancer is a highly aggressive tumour with a poor prognosis due to low early detection rates and a lack of biomarkers. Alterations in the N-glycosylation of plasma immunoglobulin G (IgG) have been shown to be closely associated with the onset and development of several cancers and could be used as biomarkers for early diagnosis. In this work, we used a well-evaluated approach (termed GlycoQuant) for the site-specific N-glycosylation profile of human plasma IgG in both healthy individuals and patients with pancreatic ductal adenocarcinoma (PDAC). By analyzing the rapidly purified IgG samples from 100 patients with different stages of PDAC, as well as 30 healthy controls, it was found that the combination of carbohydrate antigen 19-9 (CA19-9), IgG1-GP05 (IgG1-TKPREEQYNSTYR-HexNAc(4)Hex(5)Fuc(1)NeuAc(1)) and IgG3-GP03 (IgG3-EEQYNSTFR-HexNAc(4)Hex(5)Fuc(1)) can be used to distinguish between PDAC patients and healthy individuals (ROC=0.989). Additionally, the combination of CA19-9 and IgG1-GP05 can be used to differentitate between PDAC stage Ⅰ patients and healthy individuals (ROC=0.967). The study showed that the integrated quantitative method can be used for large-scale clinical N-glycoproteomic research to discover new N-glycosylated biomarkers. This could advance the development of clinical glycoproteomics.