The source coding theory, as the research information theory basis, have been paid much attention to by the people. Information in storage and transmission process often need compressed. The source coding through compression to remove the source redundancies, achieves the compression bitrate, improve communication efficiency, achieve the purpose of effective transmission signal. This paper introduces digital communication fields for language, graphic, video and other data practical source coding technology. To hoffmann coding for example introduces the source coding in digital communication, finally file compression introduced the application of the source coding the future trend of development.