In order to study the corrosion inhibition characteristics and action mechanism of octaphenyl cage polysesquioxane （OPS） in the propellant， nitramine propellant samples with OPS content of 2%， 5%， 8% and control samples with no OPS were prepared. The ablation characteristics， combustion characteristics and energy properties of the propellant were studied using a semi-closed explosive device， a closed explosive device and an oxygen bomb calorimeter. The compatibility of OPS with nitramine propellant was studied by a differential scanning calorimeter （DSC）. The microstructure， element distribution and product composition of the inner surface of the ablative tube were characterized by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. The results showed that OPS had good compatibility with nitramine propellant. When the OPS content was 5% and 8%， the ablation reduction rate was 23.9% and 36.0%， respectively. With the increase of OPS content， the ablation reduction rate gradually increases， while the energy and work ability of the propellant are reduced. The analysis of cracks， products and their distribution on the inner surface of the ablative tube showed that SiO₂ generated by OPS at high temperature was uniformly distributed in the inner layer of the tube wall， forming a protective layer with excellent thermal resistance characteristics， and reducing the erosion and scouring effect of high temperature gas and solid particles on the tube wall.