The invention discloses a high-flame-retardant polypropylene material and a preparation method thereof. The material is composed of the following raw materials in parts by mass: 60-75 parts of homo-polypropylene aggregates, 5-15 parts of homo-polypropylene powder, 10-20 parts of a brominated flame retardant, 3-8 parts of an antimony flame retardant, 1-3 parts of a flame retardant synergist, 0-10 parts of a cooling master batch, 0-3 parts of a flexibilizer, 0-1 part of a lubricant, 0-1 part of an ultraviolet light absorber, and 0-1 part of an antioxidant. The preparation method of the material comprises the following steps: 1) uniformly mixing all materials in certain proportion; and 2) adding the obtained mixture into a twin-screw extruder, carrying out high-temperature mixing and shearing, and after the obtained object is subjected to water cooling, sequentially carrying out bracing and grain-sized dicing, so that the high-flame-retardant polypropylene material is obtained. The high-flame-retardant polypropylene material disclosed by the invention is excellent in flame resistance, good in self-extinguishment, excellent in aging resistance, good in insulating property and heat resistance, not easy to deform by heating, excellent in processing fluidity, and easy to shape.