The invention discloses a cleaning fluid flow control system, which comprises a control valve, a pressure sensor, a controller, an I/P converter, a flow switch and a pin valve, wherein cleaning fluid flows through the control valve; the pressure sensor measures pressure of the cleaning fluid flowing through the control valve and outputs a pressure value; the controller receives the pressure value outputted by the pressure sensor, compares the pressure value with a target pressure value, generates and sends a current signal according to a comparison result; the controller sends a small current signal if the pressure value is greater than the target pressure value, and sends a large current signal if the pressure value is smaller than the target pressure value; the I/P converter receives the current signal outputted by the controller and delivers compressed air with corresponding pressure to the control valve; the I/P converter reduces the pressure of the compressed air delivered to the control valve when receiving the small current signal, and the I/P converter increases the pressure of the compressed air delivered to the control valve when receiving the large current signal; the flow switch measures the flow rate of the cleaning fluid; and the pin valve regulates the flow rate of the cleaning fluid. The invention further discloses a cleaning fluid flow control method.