Infrared radiation characteristics inversion for Unmanned Combat Aerial Vehicles (UCAVs) faces dual challenges from resource constraints and classified operational parameters. This study proposes a systematic framework for high-fidelity infrared radiation modeling of non-cooperative UCAVs with integrated intake and exhaust systems. Multi-view photogrammetric reconstruction with curvature control-based method is employed to reconstruct the external surfaces of the UCAV with stealthy intake and exhaust ducts. A propulsion requirements analysis model and an engine performance model are developed to determine the thrust requirements and engine performance during the cruise stage, respectively. The reverse Monte Carlo ray tracing method is utilized to simulate the infrared radiation characteristics of the non-cooperative UCAVs across the MWIR and LWIR bands. The results confirm the framework's capability to accurately invert infrared radiation characteristics of non-cooperative UCAVs.