In addition to solar radiation, numerous factors significantly influence the temperature distribution and radiation characteristics of ground targets, thereby affecting their detectability by infrared target recognition systems. Therefore, analyzing the impact of various factors on the radiation characteristics of typical ground targets is crucial. In this study, we addressed limitations in most commercial software, which either lack detailed temperature calculations or inadequately handle radiation transfer across different spectral bands and solar radiation-factors crucial for vehicle infrared radiation characteristics. We constructed an atmospheric model and selected a vehicle as the analysis target to establish a scene model of a vehicle with the grassy background. Subsequently, we calculated the temperature distribution and infrared radiative temperature distribution of the vehicle. Following this, experiments were conducted under the corresponding conditions. The comparison between the experimental results and the simulation results revealed minimal discrepancies, demonstrating the high credibility of the simulation. The analysis reveals that air velocity significantly influences vehicle temperature, contributing to distinct temperature differentials between the front and rear sides of the vehicle. In terms of external radiation effects, solar radiation significantly influences the radiation characteristics of vehicles by inducing temperature increases, particularly influencing the vehicle's mid-infrared reflective radiation. On the other hand, environmental and atmospheric radiation influence the vehicle's temperature and radiative temperature to a certain extent, particularly through reflective radiation when the vehicle's reflectance is high. This study aims to provide valuable insights for designing effective infrared camouflage patterns for ground targets.