In particular, the solid rocket motor(SRM) grain contains large cavity (Φ20~Φ40 mm) defects,may cause the products to be scrapped. In order to save the production cost, time, verify the technical risk of SRMs with large cavity defects, a 3D grain model with large cavity is established, and the structural integrity analysis of grains under low-temperature load, ignition pressurization and the combined effects, the theoretical calculations on the influence of burning surface changes are carried out, and the SRM ignition verification test is carry out. Theoretical analysis and experimental results show that there is a certain degree of stress concentration around the large cavity, under the conditions of low-temperature and ignition pressurization. There are no problems that the safety of products is affected by stress cracks caused by cavity. 4 SRMs have passed the high-pressure ignition test at high and low-temperature, compared with the ignition test curve of the SRM without cavity defect, the ignition verification results and the comparison analysis of the test curve with normal grain which fully demonstrates that even the grain with large cavity (Φ20~Φ40 mm), it can meet the requirements of complex working service conditions. The test results have great practical reference value for similar problems of other products.