Abstract: In order to quantitatively evaluate the overload stability of defective charges, a charge overload test system that can take into account both high overload pressure and wide pulse was innovatively established, and the overload stability of charges with different defects was tested. By quantifying the influence of the experimental system on the characteristic value of charge load, the correlation mechanism between charge response behavior and image gray level was revealed. By introducing the conversion factor of testing device, the overload stability evaluation model of defective charge was proposed, and the response critical pressure threshold of different defective charge was predicted. The results indicate that the overload peak value greater than 1GPa and high impulse pulse width greater than 100μs can be achieved. With the increase of defect diameter, the response level of loading response increases significantly. The critical pressure of combustion reaction decreases from 0.71gpa to 0.26gpa with the increase of charge defect diameter from 0mm to 12mm. When the defect diameter of the charge reaches 10mm, the critical pressure of deflagration reaction is 1.56GPa. With the increase of defect diameter, the critical pressure of deflagration reaction decreases to 1.25GPa when the defect is Φ12mm. The reaction critical pressure predicted by the model is within the confidence range of the experimental data surrounded by the minimum reaction overload pressure and the maximum unreacted overload pressure, which verifies the reliability of the model, and provides theoretical and experimental data support for the safe service of defective charge.