The pressure wavespeed of pipe flow is the basic physical parameter to analyze and study the stability and dynamic quality of hydraulic system. The three-sensor measurement theory was deduced based on the wave equation of the transmission pipeline, the Foster equivalent shear coefficient model was introduced for high-precision estimation of various influence factors in the hydraulic line, and the Newton-Raphson iterative method was adopted to reduce the data processing error and accurately calculate the pressure wavespeed. An on-line test platform for measuring pressure wavespeed of hydraulic pipeline was built based on theoretical derivation, realizing accurate measurement and calculation of pressure wavespeed of hydraulic system under various working conditions by MATLAB software programming. The test results show that: when the system is under the typical working pressure of 20 bar,50 bar,75 bar and 100 bar, the pressure wavespeed is about 1 320 m/s, 1 338 m/s, 1 363 m/s, 1 380 m/s respectively, and the measurement error is within ±1% in the wave speed interval with a confidence level of 95%; the pressure wavespeed of pipeline increases with the rise of the working pressure, and the function relationship between the two variables was given according to the test results; the effect of pipe material on system flexibility should be considered in the precise calculation of pressure wavespeed. The results of test and analysis have important guiding significance and reference value for the on-line measurement and estimation of pressure wavespeed in hydraulic system.