Abstract: The MOX fuel has a good future for widely application. Today, the MOX fuel technology has been developed and applied in many PWRs all over the world. But there is still no experience in China and a lot of analysis works are needed. In this paper, the decay heat of the reactor core, heat load of spent fuel pool and fission product inventories of the reactor core according to the fuel management of M310 NPP with one third of the core filled with MOX fuel assemblies are studied. Comparing the reactor core with MOX assemblies with the reactor core with UO₂ assemblies, it shows that the changes of the decay heat of the reactor core, heat load of spent fuel pool are small, and they would not be 15% greater than UO₂ fuel. The change of fission product inventories is also not large except some fission product nuclides as 135Xe and 136Cs, which are over 40% more than UO₂ fuel. The result of this study proves that the radiation characteristics of MOX fuel core changes small, and has negligible impact on the plant safety and operation.