The invention discloses an alloy material for power mechanical parts and a preparation method thereof. The alloy material comprises the components of titanium boride, aluminum, iron, manganese, nickel, lanthanum or cerium, tin, zinc, silicon, phosphorus and copper, wherein the weight percentages of the components of the alloy material are as follows: 3-4.5% of titanium boride, 17-19% of aluminum,10-11.5% of iron, 3-4.5% of manganese, 4-5.5% of nickel, 2-3.5% of lanthanum or cerium, 1-2.5% of tin, 1-3.5% of zinc, 0.5-1.5% of silicon, 0.5-1% of phosphorus, and the balance of copper. Titanium boride ceramic particles are added in traditional bronze materials for improving the hardness of casting alloy materials; and corresponding rare earth elements of lanthanum or cerium are properly addedfor further refining and improving the particle size structures of alloy internal materials, so that the strength and the hardness off the alloy materials can further meet the requirements of materials for nuclear power steam turbine wear resisting pump blocks under the precondition of no need of further forging or heat treatment of the materials.