The methoxy poly (ethylene glycol)-grafted chitosan (Chito PEG) copolymers were synthesized by activating carboxylic acid of MPEG usign DCC/NHS system and introducing MPEG into the chitosan main chains. The chitosan derivatives were characterized by FT-IR, 1H-NMR, 13C-NMR and GPC. Substitution degree(DS) of MPEG was calculated using proton integration ratio between C1 position at 4.5 ppm/acetyl group at 1.8 ppm of chitosan and methyl group of MPEG at 3.4 pp All the copolymers were souble in water over wide pH range. Futhermore, organosolubility of hydride in DMSO, DMF, Acetone and EtOH was also achived when the DS value mere than 15%.