Analysis is done on the change rules of liquid " s temperature along with the pipeline " s distance . the paper points out the defects of the const pressure wave velocity method and do some improvements on it : rebuilding the expressions of the pressure wave velocity in accordance with the simpson ' s rule 分析了管道内的流体温度随传输距离而变化的规律，并指出了此规律对管道负内压力波传播速度的影响。指出了常负压力波波速定位方法的局限性，并采用改进的负压力波定位技术，将管道内的负压力波速公式采用复化辛普森公式进行了改造。
