The invention discloses a composite fiber modified nylon material and a preparation method thereof. The composite fiber modified nylon material comprises the following components in percentage by weight: 50% to 70% of nylon, 29% to 50% of composite fibers, 1% to 20% of addition agent, wherein the composite fibers comprise glass fibers and polyimide fibers; the percentage by weight of the glass fibers to polyimide fibers is (1 to 9) to 1. Composite fiber is formed by the glass fibers and the polyimide fibers so as to modify the nylon. Therefore, the modified nylon material which has the advantages of strong intensity, excellent stability and excellent fatigue resistance is obtained, the defects that products are easy to deform and warp due to glass fibers are overcome by the polyimide fibers, the glass fibers enable the usage amount of the polyimide fibers to be reduced, and the cost is reduced. The preparation method mainly comprises two steps: mixing and performing melt extrusion, the technology is simple, complex equipment is not required to be added, the cost is low, the performance of composite high polymer materials is improved, and the composite fiber modified nylon material is suitable for industrial production.