Absolute open flowof natural gas well is not only the important indicator to reflect potential productivity, but also the foundation to determine reasonable production rate. One point method deliverability testing is a quick and effective method to determine gas well productivity. Based on one point method systematic well testing theoretical model, the systematic well testing data of Tainan Gasfield are analyzed, and the one point method empiric equation suitable for unconsolidated gas reservoir is obtained. After Error correction of the empiric equation, this method can be used tomonitor productivity changes.