Abstract: Aiming at the main production wells of Puguang gasfield, based on the analysis of reservoir lithology and acidizing fracturing fluid, the ion concentration regularity of flowback liquid and production liquid-gas ratio variance have been analyzed. And then the residual liquid flowback regularity has been summarized and the discrimination value to judge whether the residual liquid flowback is over has been provided, which is good for mastering residual liquid flowback, providing reliable guidance for rotation using of acid separator, speeding up the gas production efficiency, and at the same time providing guidance for gas well production of new blocks.