The low-dose CT scans can effectively reduce the dose exposure of patients． Ｈowever, the imaging quality will be lowered in the meantime. The way of maintaining high quality image that available for clinical diagnosis has become the main research direction in the field of CT technology. This paper summarizes the development and implementation of low-dose CT scans from the following aspects: low-dose scan implementation; statistical model of measurements; reconstruction methods and image processing methods. The research status of low-dose CT technology is also summarized. Finally, both the current research focus and the future research prospect are discussed and analyzed.