Abstract: Chang 8 reservoir in Xifeng oilfield is a low permeability reservoir with fine pore throat and high shale/sand ratio. The cause of reservoir plug was analyzed and acidizing fluid formula of acid stimulation in the block was optimized through theory and experiment. Results showed success rate of applying mud acid to stimulate corner wells is relatively higher than that of edge wells. The application effect of compound organic acid is better than mud acid which provided experiences for individual well production increase in Xifeng oilfield.