In order to simplify the monocular measurement system calibration tools and quickly adjust the scanning direction of measurement system, we design the “cross” calibration plate and pose-adjustable working stage in the experiment of measuring the cladding layer size through the monocular line structure-light sensor. The “cross” calibration plate can be used to calibrate the camera and the laser plane. The combination of the “cross” calibration plate with the pose-adjustable working stage is not only helpful to calibrate the scanning direction of the measurement system, but also avoids the errors caused by the deviation of the laser projector. In the whole calibration process, only the same calibration plate is required, so the experimental tools are simplified. Moreover, the pose-adjustable working stage satisfies the condition of fast calibration and real-time adjustment of scanning direction. The device is simple to operate, and presents intuitive calibration results. The measurement error of the cladding layer is less than 0.05 mm.