The invention discloses a lower hybrid wave power control system in a Tokamak experiment, which comprises 24 high-power klystrons. The output end of each high-power klystron is provided with a directional coupler. Incident power coupled by the directional coupler is sent to a detector after direct current (DC)-blocking through a DC-block and filtering through a filter, detection voltage coming out of the output end of the detector is sent to an amplifier, amplified voltage output by the amplifier is collected through an analog input module, processed through a power control lower computer, and output by an analog output module, and the output end of the analog output module is connected to a personal identification number (PIN) electrically controlled attenuator of a microwave preceding stage. By means of collection of the power control lower computer, PID algorithm and output of the analog input module, the lower hybrid wave power control system in the Tokamak experiment controls the PIN electrically controlled attenuator of the preceding stage and controls lower hybrid wave preceding stage power so that output power of the klystrons is controlled. Meanwhile, by means of collection of output power and status signals of the klystrons, working status of the system is judged, PID control is adjusted according to requirements so as to avoid output overshoot of the klystrons, ensure stability of the lower hybrid wave system, and meet requirements of the Tokamak physical experiment. The power control lower computer of the system adopts a cRIO system, and enables the control system to have accuracy and reliability of a field programmable gate array (FPAG) and flexibility of an ordinary industrial personal computer.