The invention discloses a high-strength and high-modulus rare-earth magnesium matrix composite material containing SiC particles for automobiles. The high-strength and high-modulus rare-earth magnesium matrix composite material comprises the following components in percentage by mass: 1.0%-15.0% of heavy rare earth, 1.0%-10.0% of yttrium and/or neodymium, 1.0%-15.0% of SiC and the balance of magnesium, wherein the sum of the components in percentage by mass is 100%. A preparation method of the high-strength and high-modulus rare-earth magnesium matrix composite material comprises the following steps: punching on a pure magnesium ingot; carrying out surface modification treatment and drying, and then enclosing SiC particles into the holes; heating and fusing the pure magnesium in a protective atmosphere; stirring, and then quickly heating; and adding other components, stirring, refining, drossing, and casting to obtain a cast ingot. The components are reasonable in proportioning, and easy to process and manufacture; the prepared high-strength and high-modulus rare-earth magnesium matrix composite material has high room-temperature strength and elasticity modulus, and relatively good plasticity; the overall performance is obviously superior to that of existing rare-earth magnesium alloy; and the high-strength and high-modulus rare-earth magnesium matrix composite material is suitable for industrial production.