Air-raid shelter is an important component of the underground space in Chongqing city. During the Anti-Japanese War period, they served as shelters for military and civilian production and life, enhancing the overall protection capacity of the city and providing effective protection for the war. Nowadays, there are problems with insufficient space utilization and unclear design concepts in the reuse of air raid shelters in the urban areas of Chongqing during the Anti-Japanese War. Therefore, specialized research on the adaptive reuse of air defense shelters in the urban areas of Chongqing during the Anti-Japanese War period is conducted. Based on relevant theories of adaptive reuse, firstly, by transforming and reusing the original functions and spaces of air defense shelters, the old functions is continued, the old functions is integrated with the new functions to expand the new functions. Secondly, the existing wartime air defense voids should be designed for adaptive reuse by expressing regional characteristics, optimizing internal spatial forms, showcasing ecological landscapes, upgrading functional efficiency, and enhancing safety performance, in order to improve and extend the efficiency and lifespan of wartime air defense voids. Finally, based on the unique regional characteristics of wartime air defense shelters, a diversified integration plan, a combination of civil defense functions and disaster prevention and rescue, and an adaptive reuse design strategy that integrates military and civilian functions are proposed, in order to better leverage the cultural and socio-economic benefits of air defense shelters in the Chongqing urban area during the Anti-Japanese War in the context of peace and war integration.