X-ray examination and CT examination are both through the X-ray imaging, but there are some differences between the two, mainly including the amount of radiation is different, imaging is different, the scope of application is different, the cost of the examination is different. 1. The amount of radiation is different: the amount of radiation in X-ray examination is below 1msv, and the amount of radiation in CT examination is mostly above 2msv. 2. Differences in imaging: X-ray images are overlapping images, while CT images are tomographic images. 3. Different scope of application: X-ray examination is mainly used for chest, abdominal physical examination and limb fracture screening, CT examination is widely used in all parts of the body, for disease diagnosis to be more clear. X-rays have a clearer picture of the organ as a whole, such as fractures, lung infections, intestinal flatulence and gas-liquid planes, etc. CT has a clearer picture of the localized lesions of the organ. Such as cranial brain, liver, chest and abdominal viscera. 4. Different examination costs: X-ray examination costs are relatively low, CT examination costs are generally 2-3 times more expensive than X-ray. Both examinations themselves have radiation, pregnancy should pay attention to avoid doing the relevant examination, the specific choice of examination program should be standardized under the guidance of clinicians.