The invention discloses an electricity generation pretreatment control method of low combustion value gas. The method includes: (1) an electricity generation pretreatment control system receives a start signal to conduct the system self-check; (2) a plurality of sensors at the entrance of the electricity generation pretreatment system detect the temperature of the gas and the concentration of methane at real time; (3) sensors at the exit of the electricity generation pretreatment system detect whether pressure is within the range of set threshold at real time; and (4) after the electricity generation pretreatment system receives a closing signal, a PLC first closes an air admission valve by control, reduces the rotating speed of a fan and starts a recycling valve, so as to lead partial gasto flow back to the entrance of the electricity generation pretreatment system and abate the gas pressure in the electricity generation pretreatment system, then the PLC stops the fan by control, closes the recycling valve and stops a refrigerant condenser, and the electricity generation pretreatment system normally closes. The control method has the functions of automatic pressurization and over-pressure protection and can guarantee the pretreatment system operates safely and reliably for long time.