Abstract: Infrared detection materials constitute the foundational components driving the advancement of infrared detection technology. Their intrinsic properties directly determine the response bandwidth, sensitivity, and stability of detectors, enabling extensive applications in military reconnaissance, security surveillance, medical diagnostics, and environmental monitoring. However, the conventional experiment-driven research and development paradigm is inherently constrained by extended cycles, high costs, and often empirical optimization processes. In this context, theoretical simulations grounded in quantum mechanics and statistical mechanics have emerged as a pivotal driving force, exerting a direct and transformative influence on the design and performance optimization of infrared detection materials. This paper reviews recent progress in the theoretical simulation of such materials, systematically outlining the principles, advances, and applicable scenarios of key computational methods, including first-principles calculations, molecular dynamics, Monte Carlo simulations, and multi-scale modeling. Furthermore, it provides an in-depth analysis of the application of these simulations to a range of prototypical infrared material systems, ranging from traditional narrow-bandgap semiconductors to quantum dots, two-dimensional materials, and topological insulators. The analysis focuses on performance modulation, defect mechanism investigation, and the discovery of novel functionalities. Subsequently, the current limitations of theoretical simulations are critically examined, particularly regarding challenges in multi-scale coupling, dynamic environment modeling, and the precise characterization of defects. Finally, prospective research directions are outlined, including machine learning-aided simulation, multi-physics coupling frameworks, and the development of closed-loop "simulation-experiment" design paradigms. This review aims to provide a systematic reference for the theoretical design and experimental optimization of infrared detection materials, thereby facilitating the advancement of infrared technology toward broader bandwidth, higher sensitivity, and lower power consumption.