An X-ray tomographic scanner comprises a ray source, a flat panel detector, a detection bed and a collection computer, wherein the ray source emits X-rays, the flat panel detector receives the X-rays, converts the X-rays into electric signals and is connected with the collection computer, and the detection bed supports a patient; a fixed support is arranged around the detection bed, a contact slip ring is arranged at the inner side of the fixed support, the ray source and the flat panel detector are fixedly arranged on the contact slip ring and arranged opposite with the same diameter and rotate synchronously, the contact slip ring rotates around the detection bed, and a movement detection device is arranged over the fixed support. Images collected by the ray source and the flat panel detector during rotation are two-dimensional projection, and the two-dimensional projection is reconstructed in a three-dimensional mode through the collecting computer to obtain three-dimensional images used for diagnosis of doctors. The use ratio of the X-rays is higher, the speed of collecting data is higher, and movement of the patient can be monitored at all times through the movement detection device.