Abstract: In order to enhance the precision of leakage detection system for SINOPEC Tanggu-Yanshan Parallel Oil Pipeline, the causes of positioning error are analyzed, indicating that the detection distance and data reading frequency have significant impacts on precision of the system. Thereby, it is propose to improve the positioning accuracy by shortening the detection distance, establishing independent data channels and increasing the detection frequency. Combing the propagation law of negative pressure wave and the inherent frequency of SCADA system, one detection point is added in Chentaizi Valve Chamber along the Tanggu-Yanshan Parallel Oil Pipeline, in order to shorten the detection distance, which has helped to effectively reduce the attenuation intensity of negative pressure wave and increase the detected negative pressure wave intensity by 50%. Through establishing independent data channels, the frequency of leakage detection system is improved from 1 Hz to 20 Hz, thus, the positioning error is reduced from 3.61 km to 0.79 km, so that the positioning precision of the system is significantly improved. This method provides guarantee for the safe, smooth and efficient operation for SINOPEC Tanggu-Yanshan Parallel Oil Pipeline.