In recent years, the military equipment used for reconnaissance has achieved high precision levels. The high-tech reconnaissance methods can often perform precise strikes on targets, greatly reducing victory in war. Two commonly used methods for acquiring hyperspectral data are hyperspectral satellite remote sensing and high-altitude aerial technology. These two imaging methods have the same reconnaissance time. The direction of light source is basically the same. Because the hyperspectral equipment is basically perpendicular to the ground, the reflected light direction usually keeps unchanged, the BRDF coefficient of the ground features is basically relatively fixed. In army application, the reconnaissance time is random, the incident angle of the sun changes all the time, and the reconnaissance diction is arbitrary, the hyperspectral position is on the ground or near the ground, the detection direction changes endlessly. The spectral curves under different conditions are greatly affected by the BRDF coefficient of the object surface. This paper analyzes the influence of the sun's altitude, azimuth and the detection angle on the camouflage and green vegetation spectrum under land-based conditions. The results show that although the reflection characteristics of the three materials are different, they present similar laws at different solar altitude angles, azimuth angles and detection angles. When the detection angle is constant for the solar altitude angle, the reflectance curves of the artificial camouflage and the green vegetation first increase and then decrease with the increase of the solar altitude angle. The green vegetation changes more obviously in the near-infrared band; for the azimuth, as the azimuth angle increases, the spectral reflectance of the three materials generally increases first and then decreases. At the same time, the reflectance during backward observation is generally larger than forwarding observation; for the detection angle, the relationship between the spectral reflectance of the material and the detection angle is not very obvious, but the three materials all have “hot spots” at different detection angles. Finally, this paper analyzes the BRDF model parameters of greenbelt vegetation and camouflage panels and obtains their reflection laws in different directions.