The invention provides a vegetable oil modified asphalt composite and a preparation method thereof. The vegetable oil modified asphalt composite comprises the following materials with content based on the total weight of vegetable oil modified asphalt in percentage by weight: 5%-30% of vegetable oil, 65%-80% of petroleum asphalt and 5%-15% at least one of natural asphalt and a high-molecular material or a mixture of the natural asphalt and the high-molecular material, wherein the mass ratio of the natural asphalt and the high-molecular material in the mixture of the natural asphalt and the high-molecular material is (0.5:1)-(4.5:1).