In order to investigate the influence mechanism of oxygenrich condition and particle concentration on the ablation behavior of silicone rubber insulation, the ablation test of a certain type of silicone rubber based insulation material is carried out based on the selfdeveloped oxygenkerosene ablation test system. A total of 0％, 5％, 9％, 15％ and 20％ of the oxygenrich conditions are designed, and each group is set with 4％, 6％, 8％ and 10％ particle concentration. The ablation rate of each sample is measured and the ablation rate, oxygenrich condition and particle concentration are plotted. At the same time, the microstructure of the sample is analyzed by scanning electron microscopy (SEM). The results show that the ablation rate of the two kinds of materials increases with the increase of the particle concentration when the oxygenrich condition is constant. When the concentration of particles is constant, the ablation rate of materials increases first and then decreases with the increase of oxygenrich condition and reaches the extreme at around 9％ of the oxygenrich condition; Particle concentration directly affects the mechanical stress of the surface of the material. The oxygenrich condition affects the formation rate of SiO2 in the material. Under conditions of low degree of oxygenrich, the amount of SiO2 could not be encapsulated in the protective fiber, resulting in a slight increase in ablation rate. And under conditions of high degree of oxygenrich, the generated SiO2 adhered to the surface of the filament, strengthens the erosion resistance and slows down the particle destruction. The effect of the particle concentration on the ablation behavior of the material is greater than that of the oxygenrich condition on the ablation behavior of the material, which is about 5 times the degree of the influence of oxygenrich condition under conditions of the experiments.