Aiming at the problem of inefficient and risky manual detection of cracks in concrete dams, a crack analysis method for concrete dams based on LabVIEW + VDM was proposed. The Vision Assistant (VA) of the Vision Development Module (VDM) was used to process the crack images. The skeleton function of VDM is combined with the morphological operation to extract the skeleton of the crack, and the particle analysis method was used to calculate the crack length, crack width and crack area. The processing method implemented in VA was used to generate script code, and then imported into the programming platform LabVIEW for debugging and GUI design. The results show that the VDM can independently complete the detection function of concrete dam cracks. The program developed based on LabVIEW helps industry personnel quickly detect and analyze cracks in concrete dams, timely diagnose and eliminate hidden safety hazards.