The reduction experiment of sinter has been taken in oxygen blast furnace atmosphere by thermal balance weight loss method. The changes of reduction RI and reduction rate RI′ have been examined, and then kinetics analysis of sinter reduction have been carried on. Results show the reduction of sinter is significantly improving in oxygen blast furnace atmosphere and the reduction RI measures up to 98.2% when the sinter is reducing at 900 ℃. With the reduction temperature increasing, the reduction rate of sinter speeds up significantly, and the end time of reduction is shorten from 117 min at 900 ℃ to 63min at 1 100 ℃. When sinter is reducing in oxygen blast furnace atmosphere，the reductive reaction is mainly controlled by the interface chemical reaction in the beginning, and then turn to hybrid controlled by both interface chemical reaction and internal diffusion about 20 min later. The apparent activation energy of reaction that sinter reducing in oxygen blast furnace atmosphere at 900 ~ 1 100 ℃ is 38.30 kJ/mol.