In order to deeply explore the mineral composition and metallurgical energy of sinter under different oxygen?rich stages,SEM?EDS and load?softening droplet equipment are used to study the change law and influence mechanism of the mineral structure and softening performance of sinter when oxygen?rich injection is used before, during and after the sintering process.The results show that the mineral composition of sinter mainly includes hematite,magnetite,calcium ferrite,magnesium spinel and silicate liquid phase.The results of SEM observation and surface scanning result show that, with the backward movement of the oxygen?rich stage in the sintering process,the type of SFCA(calcium ferrite complex) is changed from slat?like and needle?like to eroded,and it is more closely intertwined with the silicate liquid phase,the porosity decreases while and the mineral crystallization aggregation is stronger.The XRD refinement results show that the proportion of calcium ferrite in iron?bearing minerals is decreased from 76.04% to 69.77% with the backward movement of the oxygen?rich stage.The softening starting temperature(T₁₀) of the sinter obtained in different oxygen?rich stages is above 1 180 ℃,the softening interval is 99～103 ℃,the melting interval is 212～218 ℃,the dripping mass of the sinter is changed from 75.5 g to 73.0 g and finally is increased to 78.6 g,and the dripping velocity reaches the maximum value of 0.85 g/min in the later stage, due to the decrease of high melting point and the formation of low melting point substances. In the later stage of the sintering process, the slag iron separation is high, and the iron aggregation is strong, resulting in a strong dripping of the charge.