The invention provides an oxygen-coal ratio control method. A control goal of traditional oxygen-coal ratio control is only to make flow rates of oxygen, steam and pulverized coal proportional, and regardless of a reaction condition (mainly referring to temperature) of a reactor, the oxygen-coal ratio is always adjusted at a set ratio. This may lead to the result that when the temperature of the reactor is too high or too low, the oxygen-coal ratio control cannot give feedback in time. Instead, it needs to manually reset a ratio coefficient, which will inevitably lead to instability of adjustment and increase the intensity of manual operation. According to the method provided by the invention, the reactor temperature is introduced as a means for fine adjustment of the flows of oxygen, steam and pulverized coal during a stable working condition period, so that the automation degree of the whole oxygen-coal ratio control is higher, the manual misoperation is avoided, and the temperatureadjustment of the reactor is more sensitive, stable and reliable.