Abstract: A special calorimeter based on the static isothermal method under thermal equilibrium conditions was designed to measure the heat generation rate of the stainless steel. Besides, the distribution of the heat generation rate of the steel along with the reactor active axial region, as well as its relationship with the reactor power are further explored. Meanwhile, the MCNP code was also used to calculate the heat generation rate of the steel, and the accuracy of the MCNP code was verified by comparing the corresponding measurement and calculation values. The results show that the heat generation rate of the steel in the research reactor is closely related to the location and the reactor power, and it approximately changes along with the reactor active axial region in a truncated cosine curve. The maximum heat generation rate is located in about 50 mm below the center plane of the reactor, and it linearly increases with the increasing of the reactor power. At the range of the experiment, the values calculated by the MCNP code are averagely 18.1% higher than those acquired in the experiment, and it shows that the heat generation rate of the steel by the MCNP code has a guiding significance for the practical application in the research reactor.