The dearth of current discharge measuring methods of concrete pumps requires new techniques to be explored. First, the discharge measuring method of detrended fluctuation analysis (DFA) was introduced and used to extract the scaling exponent of the vibration signal collected from the hydraulic pump. Then, the scaling exponent calibrated the discharge of the pump. The analysis results showed that this technique was effective at calibrating the discharge of the pump, but had low accuracy, so the DFA increment series of extreme point method was proposed to further improve it. Using this method, the minimum and maximum scale fluctuation parameters were acquired simultaneously, then used to calibrate the discharge of the pump. Finally, the experimental results showed that the method of DFA increment series of extreme point was three times more accurate than the original DFA, and verified that the presented method provides an effective way to measure pump discharge.