The structure characteristics and adhesive property of humic substance (HS) extracted with different methods were mainly studied by terms of elementary analysis,visible spectrum,FT-IR spectroscopy,viscosity,adsorption and pelletizing experiments.The results show that HSs extracted with new method (HS-a) own higher degree of aromatization and polymerization,larger relative molecular mass and more polar functional groups than HS extracted with usual method (HS-b).The viscosity of HS-b is about 30-40 mPa·s lower than that of HS-a.The maximum adsorption amounts of HS-a and HS-b onto iron concentrates are 9.11 mg/g and 8.08 mg/g,respectively.Meanwhile,HS-a has a better performance than HS-b in the practical application for pelletizing of iron concentrates.The difference in agglomeration behaviors with iron concentrates lies in the differences of the strusture characteristics of HSs.With higher content of polar functional groups,larger relative molecular mass and viscosity of HSs,the agglomeration behavior is improved.