Haff disease (HD) is unexplained rhabdomyolysis caused by the consumption of fishery products in the previous 24 hours. Altered N-glycosylation has been to be associated with many diseases or cancers progression, while it is ambiguous whether serum N-glycosylation is also correlated with this disease. Initially, we explored the alteration of the concentrations of immunoglobulin G (IgG), the most abundant immunological protein involved in immune system, in haff disease patients. Strikingly, the level of IgG was substantially lower in haff disease than that in healthy controls with P-value less than 1.0E-7, suggesting possible immunological depression in the onset of this illness. With high-throughput MALDI-MS technology, we identified a total of 55 N-glycans in serum from healthy controls (HC) and haff disease patients. Statistical analysis showed the relative abundance of 23 glycans in serum were significantly different between the patients and normal groups. Further evaluation of the diagnostic performance demonstrated 17 glycans obtaining at least moderately accurate area under the curve (AUC) score with preferable sensitivity and specificity, of which 2 glyans deserved accurate diagnostic merits. Furthermore, the analysis of glycan features showed that this disease associates with increases in digalactosylation, disialylation and total sialylation, with concurrent decreased mannosylation, agalactosylation, mono-galactosylation and bisected GlcNAcylation. Notably, this study is the first to comprehensively probe into the molecular changes in haff disease. These findings paves a new way underlying the biological mechanisms of this illness and provide the criteria for drug development and therapy treatment.