The invention discloses a high-rigidity and toughness balance, anti-stress whitening and halogen-free flame retardant polypropylene composite material and a preparation method thereof. The composite material consists of the following raw materials in parts by weight: 32-96 parts of polypropylene, 0-30 parts of talcum powder, 1-20 parts of cage-like polysilsesquioxane, 1-15 parts of elastomer, 0.1-1 part of an antioxidant and 0-2 parts of other aids. The high-rigidity and toughness balance, anti-stress whitening and halogen-free flame retardant polypropylene composite material and the preparation method thereof disclosed by the invention have the advantages that through introducing cage-like polysilsesquioxane nanometer particles in a traditional talcum powder reinforced polypropylene baseformula and compounding two different scale systems, the rigidity and the impact resistance of the polypropylene composite material can be significantly improved; meanwhile, the nano-sized cage polysilsesquioxane particles can act as nucleating agents, so that the crystallinity of the polypropylene composite material is improved; in addition, the better carbon formation effect of the cage-like polysilsesquioxane can improve the oxygen index of the polypropylene composite material and solve the problem of easy combustion of the polypropylene composite material, so that the polypropylene composite material can resist stress whitening while having high-rigidity and toughness balance property and is good in flame retardance.