Abstract: This article proposes HYSYS computation model by researching on the operation data of cryogenic unit in Daqing Gas Company. Comparative analysis shows that the computation model agrees well with operation data, which corroborates the validity of the computation model. It was concluded that cryogenic unit can recovery ethane greatly by analyzing the components of associated gas. The model has advantages in adjusting and optimizing parameters, improving production rate, reducing energy consumption to the existing or proposed new cryogenic unit.