The invention discloses a method for setting a fuel component damage monitoring alarm value. The method comprises the following steps: measuring the power level P of a reactor in real time to form a database {P}, measuring the activity level A of radionuclide in a cooling agent in real time, and collecting the radioactive measurement result of the cooling agent and the power level to form a database {A,P'}; analyzing the radioactive measurement results of typical fission product nuclide under different power levels, wherein if the measurement result is 3 times less than the measurement resultin the database under the same power level, the fuel component is not damaged in the measurement period, and the measurement results represent the expected value of the reactor when the fuel componentis not damaged; and analyzing the historical measurement results by aiming at a certain power level to obtain the expected value when the fuel component is not damaged under the power level, and multiplying the expected value by 3 times to serve as an alarm value for the fuel component damage monitoring under the power level. According to the method, the alarm value related to the power of the reactor can be provided by aiming at the specific operation condition of the reactor and combining the historical measurement data.