A method for controlling MOX pellet sintering atmosphere comprises the following steps that 1, a MOX green ware body which is obtained through pressing is selected; 2, gas replacement is conducted; 3,the MOX green ware body obtained in the step 1 is heated in a sintering furnace to be 600 DEG C and then subjected to heat preservation for 1-5 hours, and therefore zinc stearate and volatile impurities in the MOX green ware body are discharged; 4, sintering and heating are conducted; 5, high-temperature heat preservation is conducted, specifically, dried Ar-H2 is pumped into the sintering furnace at the speed of 2-25 L/min, air pressure in the sintering furnace is maintained between 8 KPa and 18 KPa, and pumping is stopped after heat preservation is conducted for 2-12 hours; and 6, cooling is conducted, specifically, the dried Ar-H2 is pumped into the sintering furnace at the speed of 0.5-3 L/min, positive pressure in the sintering furnace is controlled to be 10-18 KPa, and exhausting and blow-on are conducted till the temperature of the sintering furnace is lower than 40 DEG C.