The historical buildings from the Anti-Japanese War in Chongqing serve as significant material witnesses to the urban memory of the rear area during the war and represent spatial texts interwoven with mountain architectural forms and wartime social life. Addressing issues such as diverse types, complex sites, scattered data, and the disconnection between Conservation and dissemination, this paper introduces technologies such as HBIM (Historical Building Information Modeling), AI semantic segmentation, knowledge graphs, digital twins, 3D Gaussian Splatting (3DGS), and WebXR. It proposes a digital Conservation pathway of “multi-source collection—Scan-to-HBIM—semantic enhancement—digital twin—multimodal dissemination”. Using digital models of historical buildings from the Anti-Japanese War in the Nanquan area as samples, the paper compares modeling and dissemination strategies across different Conservation levels, spatial scales, and utilization objectives, focusing on cases such as Tingquan Building, Kongyuan, Kong Lingjun’s Villa, Kongyuan Administrative Building, Lin Sen Bathhouse, Wei Lu, the President’s Residence, Bamboo Grove Villa, and the former site of the Research Department of the Central Political School. The study suggests that digital Conservation of historical buildings from the Anti-Japanese War in Chongqing should form a hierarchical system consisting of “archive layer—management layer—monitoring layer—dissemination layer”. High-precision collection and HBIM ensure authenticity, knowledge graphs and digital twins support continuous updates, and 3DGS, panoramic tours, and WebXR enhance public accessibility, serving Conservation decision-making, academic research, course instruction, and social sharing.