Abstract: AIM: To characterize the profiles of N-glycans in highly glycosylated protein recombinant human erythropoietin (rHuEPO). METHODS: Capillary gel electrophoresis (CGE) of sugars in recombinant human erythorpoietin derivatized by reductive amination with 8-aminopyrene-1,3,6-trisulfonate(APTS) and detected by laser-induced fluorescence (LIF) has been performed to study the relationships between structure and bioactivities of rHuEPO. RESULTS: The results showed that the CGE-LIF profiles of N-glycans in rHuEPO from the same cell-line were almost identical, but clear different profiles emerged when the sample was from different expression vector. Significant differences in CGE-LIF mappings of rHuEPO with different in vivo bioactivities were also observed. CONCLUSION: The approach developed in this article can be used to control the first order structure of rHuEPO by combining with peptide mapping.