The present invention discloses a high-performance PBT composite material and a preparation method thereof, wherein the high-performance PBT composite material comprises, by mass, 60-80% of PBT, 10-15% of a fire retardation agent, 5-15% of glass fibers, 3-10% of a toughening agent, 0.5-3% of micron calcium oxide, 0.1-0.3% of a surface treating agent, 0.1-0.5% of a 1076 antioxidant, 0.1-0.5% of a 168 antioxidant, and 0.1-1% of modified ethylene bis fatty acid amide TAF. The high-performance PBT composite material of the present invention has beneficial effects of excellent fire retardation, excellent processability, good impact toughness, low warpage, and good size stability, is added with the appropriate amount of the micron calcium oxide to improve the mechanical strength, the electric leakage resistance and the heat resistance so as to provide the good comprehensive performance, and provides good practical values and prospects in the fields of chemical industry, machinery, electronics, electrical appliances, building materials and the like.