The embodiment of the invention discloses a control method and system of a blow-down pump control system. The blow-down pump control system comprises a main chip, display equipment, a water level sensor, a buzzer, an indicator lamp and a blow-down pump, wherein the main chip is respectively connected with the display equipment, the water level sensor, the buzzer, the indicator lamp and the blow-down pump. The blow-down pump control system and method which are disclosed by the invention have the advantage of high reliability.