The utility model belongs to a tobacco leaf detection technology in a tobacco leaf processing process. The invention relates to visual detection technology of stem content in tobacco leaves. The invention relates to a detection device, in particular to an X-ray-based detection device for a stem-containing structure in leaves. The device comprises an X-ray generating device, a belt conveying device, an X-ray detector and a signal analyzing and processing system, and is characterized in that the belt conveying device is horizontally arranged, and the X-ray generating device and the X-ray detecting device are correspondingly distributed on the upper side and the lower side of the belt surface of the belt conveying device and are kept on the same optical axis; And the X-ray generating device and the X-ray detecting device are respectively connected with the signal analyzing and processing system. The device can automatically identify and count the size data of the tobacco stems, and quickly and nondestructively measure the content of the tobacco stems, so that the production efficiency is remarkably improved, the labor intensity is reduced, and the production raw material quality is ensured.