The invention belongs to the safety inspection field and provides a material calibration system and calibration method of a dual-energy X ray safety inspection device. The system comprises a material test box, an image acquisition module, an automatic calibration module, a training calibration module and a material list generation module which are sequentially connected. The calibration method comprises the following steps: the image acquisition module acquires images of the material test box; then, the automatic calibration module analyzes the images, and extracts high-energy and low-energy data of organic glass, duralumin and low-carbon steel with different thicknesses from the images; the material list generation module automatically generates a material list; debugging personnel can check whether the material resolution capacity of the dual-energy X ray safety inspection system meets the requirements of indices; if so, the material list is output; and if not, the dual-energy X raysafety inspection system is moved to the training calibration module, and the training calibration module regulates individual points on the automatic calibration curve to vertically move the points and generates the material list. The invention realizes the automatic calibration of the material and has a training calibration function for helping the automatic calibration process, thereby greatlyimproving the technical indices of the existing product.