It is crucial to fully master the mechanical properties of building components for ensuring the safety of infrastructures during service. The laboratory deformation test is an important way to study the mechanical properties of building components. At present, there is still a lack of a combination of high-efficiency, high-accuracy, and low-cost measurement methods for laboratory deformation tests. To address the issue, a method is proposed to measure the deformation of building components by using the structured light technique in this paper. It is applied to the axial tensile test of the dog-bone specimen, and the 3D full-field displacement of the dog-bone specimen is obtained by calculating the established deformation tracking model. The experimental results demonstrate the deformation measurement accuracy is at the millimeter level and can meet the accuracy requirement in the laboratory. Furthermore, the results are consistent with the way of force and the deformation mechanism of the dog-bone specimen. This paper presents a novel method for the deformation measurement, which provides a reliable analysis basis for studying the mechanical properties of building components.