Abstract: Designing converting frequency flow control system, improving the frequency converter control method, combining the standard voltage output mode and the voltage detection module into the inverter feedback control system, and the inverter terminal voltage is adjusted in real-time for adjusting the pump flow output. There is the linear relationships between the inverter and the output flow of the pump. The relationships between the frequency and flow of the three pumps under different combinations are tested. The experiments show that when a pump works, the frequency and flow linearity reach 0.99; however, when several pumps work, the frequency flow relation changes and correlation coefficient is reduced. Therefore, for the multi-pump system, it is necessary to use the combination calibration method to calibrate the frequency flow relationships of different pump combinations, and the experiments by the Yongjiang model have showed the rate of flow control deviation is less than 0.5%.