Structured light 3D reconstruction technology has been widely used in industrial detection. Nowadays, the more miniaturized and higher-precision industrial detection technology is becoming more important. The telecentric lens has many excellent characteristics, such as small perspective error, small lens distortion, less imaging distortion, and large depth of field, which attracts more attention. In this paper, the traditional lens is used to replace the camera lens in the traditional structured light system with the telecentric lens. Through the improvement of the traditional two-step calibration method, the affine model of the camera is calibrated, and then the calibrated camera is used to calibrate the parameters of the projector. The experimental results show that the telecentric structured light system can achieve high-precision and high-resolution 3D reconstruction in a small field of vision, and has an increased depth of field. It can be used for high-precision 3D detection of semiconductor devices and micro-components.