Abstract: Producing performance study is a routine but important, at the same time rather complicated work. Especially to the offshore oil and gas felds, there are more uncertainties in the producing performance of gas reservoir and some differences in the study method due to the enormous investment, high cost and diffculty in data acquiring. Therefore, the processizing of the study method for the producing performance of offshore gas reservoir will beneft the novice to work in the role quickly and conduct the analysis effectively, and may provide a reference to establish the effective work flow and methodology of performance study.