Abstract: For the current air separation technology and the application of an internal compression process， the three internal compression process flow， best after heat stress， the hot end temperature difference and expander in smoke temperature detailed analysis has been done for the factors affecting energy consumption， and the research and discussion.Combining with the development of the current state of the air separation technology， and puts forward the energy saving development direction and measures of the air separation system， hoping to promote the development of air separation industry.