Abstract: The preliminary studies on the fusion-fission hybrid reactor were performed with the MCNP5 and MONK9A codes. The cuboid fuel assemblies and tritium-generating assemblies placed in sequence on the outside of the first-wall of the plasma formed the fission zones and tritium-generating zones. Studies were done on the fusion-fission hybrid reactor loaded with depleted uranium fuel, natural uranium fuel, depleted uranium MOX fuel and natural uranium MOX fuel, respectively. The power-amplifier factor and the tritium-generating factor can satisfy the design criteria throughout the cycle when using the last two types of fuel. A uranium-plutonium fuel cycle strategy for the fusion-fission hybrid reactor is preliminarily discussed based on the analysis of isotopic content change versus the burnup.