Abstract: With development of bio-technique, more and more proteins were applied as clinical approaches. However, the protein homogeneity, especially the N-glycosylation limited the further research and application of these protein drugs. The analysis method for N-glycans is believed to be critical in protein drugs development. To enhance the N-glycans isolation efficiency and accelerate the pretreatment, a new strategy was built on ultrafiltration-devices. New methods increased the isolation efficiency of N-glycans containing N-acetylglucosa­ mine with 10%-20%. The degrading of N-glycans containing sialic acids was also minimized with this method. 20%-100% more N-glycans with sialic acids were isolated. The pretreatment was finished within 30 min. Coupled with HPLC-HRMS, an effective and reliable strategy designed for protein drugs N-glycans analysis were developed.