The effects of ZrO₂ and ZrB₂ on combustion performances of screw extrusion double-based (DB) propellant composed of 57% of NC, 33% of NG, 0.7% of carbon black and copper salt, 2.0% of lead salt and 7.3% of other additives were studied. Their reaction mechanisms were explored by steady combustion photos and the temperature distribution of combustion zone. The results indicate that when lead/copper combustion catalysts are partly replaced respectively by ZrO₂ and ZrB₂, the burning rate of the DB propellant at 7 MPa can increase, and its low pressure combustion plateau moves to above 7 MPa, and is broadened to 13 MPa, and with decreasing the granularity of ZrO₂ and ZrB₂, the burning rate of propellant increases, showing that ZrO₂ and ZrB₂ have better catalytic effects on this propellant.