Escherichia coli（E.coli）was used as a model microorganism to evaluate the disinfection efficiency of ozone under micro-bubble ozonation and macro-bubble ozonation.Disinfection of E.coli with ozone in the presence of acid red 3R and kaolin were investigated.A comprehensively research was investigated on various ozone dose on inactivating continuous flow reactor and contact times,whose concentration was 5mg/L and 100 mg/L of kaolin which was added with activated carbon（AC）of 100 mg/L as a catalyst were used as suspended solids.Moreover,inactivation of E.coli in microbubble ozonation which contained acid red 3R and kaolin depicted that inactivation efficiency was low.The results of this study showed that microbubble ozonation method is better than macro-bubble for disinfection of E.coli in the drinking water treatment.In additional,decay of dissolved ozone concentration under micro-bubble ozonation in the presence of acid red 3R and kaolin is faster hence contributes to lower exposure of E.coli cells to the disinfectant and this contributes to high log cell concentration of E.coli.Na2CO₃ concentration was 1.5g/L and CH3 COONa was 1.16g/L,respectively.Solution buffered with phosphate at pH 10.09 and pH 7.57.The results showed that dissolved ozone concentration was being inhibited by the free radicals and ozone molecular was not responsible for inactivation of E.coli.H₂O₂,which is regarded as initiator was also investigated on its influence for disinfection of E.coli when combined with ozone under microbubble ozonation.Hydrogen peroxide conditions were 0.003 and 0.0006 mg/L,and pH were 7.57 and 7.53.Higher hydrogen peroxide leaded to low treatment efficiency than low concentration.