In microwave circuit and aerial system, impedance matching is very important.Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have already adopted liquid stub tuner to replace the conventional stub tuner. It is urgent to develop a control system of the liquid stub tuner.This paper mainly introduces the design and realization of the liquid stub tuner control system ,and briefly introduces its three controlling functions: local control, remote control and computer control.