Abstract: Flow blockage accident often happens in research reactors with plate-type fuel assemblies.In this paper,the flow blockage accident of China Advanced Research Reactor（CARR）is analyzed on the assumption that the inlet of one assembly is blocked when the reactor is operated at the rated power.The reactivity,reactor power,pressure,flowrate,temperature that is changed with time in the accident is calculated with Relap5/Scdapsim\Mod3.2.The effect of the blocked standard fuel assembly on the ambient fuel assemblies is also given.The results show that the blocked assembly will melt but it does not cause the burnout of the rest assemblies.It proves that this type of accident can be controlled within the limit by the safety measures for CARR.