The acousticbased leakage localization error for gas pipelines using crosscorrelation analysis is large due to the error of acoustic speed and time delay estimation. A leakage localization method based on delayandsum is proposed in this study. Two acoustic sensors are deployed in two sides of the leakage position to obtain two kinds of acoustic speed by using delayandsum to estimate the time delay of the signal in each side. Then, the time delay between two sensors is determined by leakage position. The weight vector can be obtained by using timedelay expression to weight the output of linear array. Hence, localization can be determined by searching the peak of weighted output. Experimental results show that a more stable output can be achieved by using delayandsum to estimate the time delay of 37 kHz component. The delayandsum method has a mean error rate of 204% while the rate of the crosscorrelation method is 909%. The accuracy of the acoustic method can be improved by calculating acoustic speed and localizing based on delayandsum with linear array.