Abstract: In the fuel assmebly of the presurized water reactor, the high-order resonance interference effect between adjacent fuel rods of different fuel types is studied. Based on the method of solving ultra-fine-group slowing-down equation and the embedded resonance calculation method, the specific type of problems is calculated. Numerical results show that the high-order resonance interference effect increases with the reduction of the moderator density and has some influence on the precision of resonance calculation. The maximum relative cross section error reaches 10% in the fuel assembly mixed with uranium dioxide fuel and plutonium uranium oxide fuel. By improving the embedded resonance calculation method, the high-order resonance interference phenomenon can be treated effectively, and the resonance calculation precision of the fuel assembly with complex design can be improved. Results show that the relative error of the resonant section is reduced to less than 3% in the multi-fuel mixing components under various working conditions.