ASU is the upstream process unit of ZhongtianHechuang project and will mostly supply oxygen for gasifier and the nitrogen needed by the project, the ASU is of the features of proven technology, advanced process and low energy consumption. Since the ASU went into test run preparation, high attention was paid by SNEC and project team. All the departments of project team and client’s process department worked together and overtime for list punching and elaboration of commissioning program; the mechanism of “five parties joint inspection” was set up with regard to the stringent cleanness specification for piping in commissioning, and full process monitor was imposed on the key position especially the oxygen piping, thus the cleanness specification was effectively met; in terms of safety, project team imposes real time monitor on field operation by operation permits, the ISBL valves and blinds were checked and recorded everyday as last control for safety. Safe and favorable conditions were created for successful startup of unit by the unified effort by project team.