An extracellular chondroitinase ABC (ChSase ABC,EC.4.2.2.4) produced by cultivating Acinetobacter sp.C26,was purified to homogeneity from the supernatant by ammonium sulfate fractionation,Q-Sepharose Fast Flow and Sephadex G-100 chromatography.The 76kDa enzyme was purified 48.09-fold to hornogeneity with specific activity of 348.64U/mg,Using the chondroitin sulfate A (CS-A) as substrate,the maximal reaction rate (Vmax) and Michaelis-Menten constant (Km) of ChSase ABC were found to be 10.471 μmol/rnin/ml and 0.105 mg/ml,respectively.The enzyme showed t he highest activity at the optimal conditions of pH 6.0 and 42 ℃,respectively.This enzyme was stable at pH 5-10,5-9 and 5-7 at 4℃,37 ℃ and 42 ℃,respectively.Investigation about thermal stability of ChSase ABC displayed that it was stable at 37 ℃ ChSase ABC activity was increased in presence of Na+,K+,Mn2+,1,10-phenant hrolin and strongly inhibited by Cu2+,Hg2+,Al3+and SDS.These properties suggested that ChSase ABC from Acinetobacter sp.C26 bring promising prospects in medical and ind ustry applications.