Abstract: The U-Mo alloy fuel has several advantages such as high U density, good irradiation stability and simple reprocessing, which is an ideal choice of future research reactor. No changing the main structure of China Advanced Research Reactor (CARR), the core physics scheme study was performed based on the fuel change from U₃Si₂-Al dispersion fuel to U-Mo alloy fuel. Through comparison and analysis of neutron fluence rate and operation cycle, the optimal core physics design scheme was given. There are better design parameters in the core scheme, which could decrease the cost of fuel and increase the economy of reactor operation.