The present invention relates a vertex optimization method and system using a depth image in workspace modeling, the method including generating a workspace model by scanning a workspace and modeling the workspace; generating a vertex image by projecting vertices in the workspace model generated in the scanning of the workspace; generating a depth image by expanding the vertices in the vertex image generated in the generating of the vertex image; and resampling the workspace model generated in the generating of the workspace model using the depth image generated in the generating of the depth image. Accordingly, the depth image can be generated from a vertex image obtained by projecting spatial data scanned through a 3D scanner onto a virtual wall, thereby uniformly aligning non-uniform vertices and filling gaps in which no vertices are generated.