Abstract: With the rapid development of thermal analysis instrument and measurement technology, it is possible to measure neutron fluence by measuring the change of thermal properties of irradiated materials. In this paper, the modulated differential scanning calorimetry (MDSC) method was adopted to measure the neutron fluence rate of the reactor with the change of the reversible specific heat capacity of the boron containing materials irradiated in the reactor. The feasibility of this method to measure neutron fluence rate in the reactor was discussed in both theory and experiment. The principle and experimental method for measuring neutron fluence rate in the reactor by reversible specific heat capacity method were introduced in detail. The application of this method in measuring the neutron fluence rate of high fluence reactor is prospected in the future.