Abstract: Objectives: With the rapid development of domestically manufactured aerial cameras in China, systematic verification of their geometric accuracy in digital aerial photogrammetric mapping has become essential for promoting their widespread applications. This study focuses on the domestic AFC-900 ultralarge-format aerial camera, systematically verifying its geometric accuracy in large-scale digital aerial photogrammetric mapping across various terrains by using the self-developed fully automatic digital photogrammetric system Imagination. Methods: Aerial images with a 0.04 m ground sample distance (GSD) were acquired over a typical urban flat terrain in northern China using a Yun-12 aircraft. The GPS data observed by the onboard POS AV610 system were processed via precise point positioning (PPP) to determine exposure station coordinates in the WGS 84 reference frame, followed by GPS-supported aerial triangulation (AT). A digital surface model (DSM) was then automatically generated using an optical-flow-field-based dense image matching method, and a digital orthophoto map (DOM) was directly produced from the derived dense 3D point clouds without manual intervention. The geometric accuracies of the AT, DSM and DOM were objectively assessed using ground check points (GCPs) under fully automatic conditions. In addition, a digital line graphic (DLG) was manually compiled from the AT results on a commercial digital photogrammetric workstation, and the accuracies of the DSM, DOM and DLG products were further evaluated through field inspection by a professional surveying and mapping quality inspection agency. Results: The results show that the GPS-supported bundle block adjustment based on AFC-900 images achieved root mean square errors of ±0.088 m in planimetry and ±0.096 m in elevation, both better than 2.5 GSD. The final mapping products reached planimetric and vertical accuracies of ±0.214 m and ±0.187 m, respectively. Conclusions: These results demonstrate that the AFC-900 satisfies the accuracy requirements of China's current specifications for 1:500 topographic mapping in flat terrain areas and has strong potential for efficient and high-precision large-scale digital photogrammetry. The study provides an important technical basis for its broader application in surveying and mapping, land management, urban planning, and real-scene 3D city modeling in China.