Benggang is a special type of landform type that exists in the hilly areas of tropical and subtropical hills in the south of China. The water and soil erosion occurring on the collapsed land is different from other types of erosion. Its occurrence and development are characterized by uncertainty and rapidity, which seriously threaten the ecological environment and human settlement security. The intrinsic geotechnical characteristics of the soil are a major factor affecting its formation and development. The unconfined compressive test plays an important part in the study of the mechanical properties and failure modes of the soil in the collapsing region. The near-sight measurement technique is now used for the unconstrained resistance. The lateral deformation of the soil samples in the pressure test was sampled and the image information was digitized using matlab. The deformation of the soil with different mechanical properties was analyzed by the displacement information of the marked points and the overall contour deformation and other information. Results showed that in the unconfined compressive strength test, there was no significant difference in the overall deformation of the different soil samples. In one sample, there were significant differences in the displacement of different markers. The close-range photogrammetry technique can well compensate for the lack of the unconfined compression test and it also has a broad space for development in the field of soil and water conservation.