Protein N- glycosylation is one of the major post-translational modifications in eukaryotic cells. In plants, complex N-glycans are important for developmental programs and immune responses. In animals, Malectin selectively binds carbohydrates for diglucose and high-mannose N-glycans and forms a stable complex with an ER-resident trans-membrane protein, ribophorin I. The co-expression of malectin and ribophorin I significantly enhanced the association between malectin and a folding-defective protein and reduced its secretion; However, it was not reported that Malectin was involved in the glycosylation process in plants. Therefore, in this study, we used a proteomics approach to compare N-glycosylated protein differences between wild-type and the mutant. Our data suggest that the disruption of OsMLD1 obviously affects the N-glycosylation process, implying that OsMLD1 may play an essential role in backup glycoprotein quality control.