3D lazer scanners with motor-driven X-Y stage are often used to measure the surface roughness of corroded specimens. However, due to the limitations of these apparatuses, the specimen surfaces, such as upper surface, lower surface and side surfaces, must be measured indivisually by changing the locations of the specimen or the lazer scanner. Therefore, in order to generate the 3D numerical models of corroded specimens, it is necessary to unify these indivisual surface data sets. Herein, an accurate method is proposed to unify adjacent two indivisual surface data sets by utilizing the centers of three globes as benchmarks common to the two surfaces. The surface data of the globes measured by the lazer scanner can be used to identify their center locations accurately. The repetition of this procedure leads to the generation of a fully 3D-numerical model.