The invention relates to a method for judging the rice water amount of a heater. The method comprises the following step of: 1, timing from zero by using a first timer, timing a time interval delta t from zero by using a second timer, and entering a step 2, wherein n is equal to 1; 2, when the first timer reaches preset total working time t0, entering a step 6, otherwise, entering a step 3; 3, when delta t reaches a preset time interval delta tn, entering a step 4, otherwise, entering a step 5; 4, retiming from zero by using the second timer, adding n with 1, updating the delta tn and Tn, and entering the step 5; S, when a detected temperature Tb is higher than or equal to the corresponding judged temperature Tn which corresponds to the delta tn, stopping the heater from heating, timing heating stop time by using a third timer, entering the step 2; and when the detected temperature Tb is lower than the judged temperature Tn which corresponds to the delta tn, heating with the heater by using power P2, and entering the step 2; and 6, judging the rice water amount according to the length of the heating stop time accumulated by using the third timer.