The importance of PACS has been recognized and progress of its technologies has rapid speed for the past 15 years. The Implementation of PACS still has many technical problems to solve. In this paper

firstly

the key technologies of PACS are presented and analyzed. Secondly

the standardization of Digital Imaging and Communications in Medicine of ACR/NEMA DICOM3.0 is described. Thirdly

Some software functions in image archiving

processing and display are discussed. Fourthly

a scheme for saving large data of medical imaging is proposed. Finally

the paper points out that in order to follow the stream of medical information

it is necessary to study and master the key technologies of PACS. It should to study and establish the standard for communication and store of medical image. In present condition

it should to study and set up small PACS. And large PACS will be established when there are mature conditions.