The feasibility of hydrogen peroxide oxidation and alkaline hydrolysis for the excess sewage sludge reduction were investigated. Sludge particle disintegration by hydrogen peroxide and alkaline hydrolysis was showed through the test of total solid concentration. particle size distribution and viscosity. The increase of settlability of sludge was also confirmed. When alkaline hydrolysis was applied as a pretreatment of hydrogen peroxide oxidation, the sludge particle disintegration was accelerated and the settlability of sludge was improved more.