The invention discloses a rare-earth chloride and intumescent flame retardant synergic flame retardance polypropylene composite and a preparation method thereof. The composite is prepared from rare-earth chloride, an intumescent flame retardant and polypropylene. Rare-earth chloride is introduced into an intumescent flame retardant flame-resistant polypropylene material, rare-earth chloride and the intumescent flame retardant can achieve a synergic flame retardance effect, and the physical and mechanical performance of the intumescent flame retardant flame-resistant polypropylene material is effectively improved while the use amount of the intumescent flame retardant is reduced.