The invention discloses a kiln air-fuel ratio adjusting system comprising burners, a thermocouple, a temperature control instrument, a fuel gas adjusting valve, an air adjusting valve and an air-fuelratio controller, wherein the burners and the thermocouple are arranged in a kiln. The thermocouple is connected with the temperature control instrument. The fuel gas adjusting valve is installed on afuel gas pipeline of the burners. The air adjusting valve is installed on an air pipeline of the burners. The kiln air-fuel ratio adjusting system is characterized in that the temperature control instrument is connected with the air ratio controller, and the air-fuel ratio controller is connected with the fuel gas adjusting valve and the air adjusting valve. According to the sintering technologies of different green bricks, the kiln burners at different sintering stages have different best air-fuel ratios, meanwhile, when the kiln is empty and the burners are in the low-fire-power state, combustion air can also be automatically adjusted to be in the best ratio to fuel gas, the kiln burners are completely automatically controlled by the air-fuel ratio controller in the whole process, and the best energy-saving effect of the kiln is achieved.