Rapeseed protein is a kind of complete protein with excellent amino acid composition. And its high nutritional values make the rapeseed protein a potential edible food ingredient. The objective of this study was to investigate the effect of different extraction methods， namely conventional alkali-solution and acid-isolation extraction and weak electric field extraction on the functional properties of rapeseed protein isolate， e.g.， amino acid composition， sulfhydryl/disulfide content， secondary structure， surface hydrophobicity and so on. The results show that the surface hydrophobicity of ERP was 5.776 ± 0.222， which was greater than that of CRP (4.803 ± 0.060). So the emulsifying property， emulsifying stability and oil absorption capacity of ERP were better， the datas were 49.95%， 90.85% and 166.18% respectively. The disulfide bonds content of ERP and CRP were 47.51 and 36.67 μmol/g， respectively. According to the circular dichroism， the proportion of α-spiral and β-turn in ERP is higher than CRP. Overall， the rapeseed protein isolate with different extraction methods demonstrated distinct functional properties.