Abstract: During severe accidents in pressurized water reactor (PWR) nuclear power plant, a large amount of hydrogen is produced due to zirconium water reaction, which seriously threatens the safety of the reactor. Passive autocatalytic recombiner and hydrogen igniter are effective prevention and mitigation measures to reduce the hydrogen risk in containment for PWR nuclear power plant. At present, passive autocatalytic recombiners or hydrogen igniters are arranged at different locations in the containment. In the study of hydrogen elimination effect in containment, lumped parameter program or theoretical calculation method are often used. However, lumped parameter program is difficult to give the effect of hydrogen distribution. With the development of computer technology, computational fluid dynamics (CFD) method has been more and more applied in the field of nuclear power safety. CFD code can also be used to simulate the hydrogen distribution and evaluate the effect of passive autocatalytic recombiners in different compartments during severe accidents. For each passive autocatalytic recombiner supplier will provide the hydrogen elimination rate formula of the passive autocatalytic recombiner, there are different methods to simulate the passive autocatalytic recombiners in containment, such as, by modeling the structure of passive autocatalytic recombiners in detail and choose the complex chemical reaction model, the actual reaction process inside the passive autocatalytic recombiner can be simulated. Or the hydrogen elimination rate is calculated through the experimental formula provided by the supplier, and the source term of each component in the species functions is modified. In this paper, a novel and simplified CFD simulation method was applied to model the hydrogen elimination effect of passive autocatalytic recombiner prototype, to be specific, passive autocatalytic recombiner was treated as black box, the flow rate and composition of gas at the inlet and outlet of passive autocatalytic recombiner were set as boundary conditions. Then the method was used to simulate and optimize the layout of passive autocatalytic recombiners in local compartment of nuclear power plants, the conclusions show that the validation of the simplified simulation scheme of passive autocatalytic recombiners is verified, and the calculated hydrogen elimination result can fit well with the experiment data. The hydrogen elimination rate of passive autocatalytic recombiner at a higher position is larger than that at a lower position, and the overall hydrogen concentration in the compartment is lower. However, the phenomenon of local hydrogen accumulation at the bottom of the compartment may happen if passive autocatalytic recombiner is set at a higher position.