The invention discloses an ionomer modified polypropylene composite material generated by an in-situ reaction and a preparing method thereof. The ionomer modified polypropylene composite material generated by the in-situ reaction comprises, by mass, 39-93 parts of polypropylene resin, 3-40 parts of mineral powder, 3-10 parts of maleic anhydride grafting elastomers, 0.5-10 parts of metal salts, 0.1-0.4 part of antioxidant and 0.3-1 part of lubricant. The ionomer modified polypropylene composite material generated by the in-situ reaction has excellent comprehensive performance, the flexural modulus of the material can reach 1860 MPa, the notch impact strength of a cantilever beam can reach 15 KJ/m<2>, the melt index is 13.2 g/10 min, the obdurability and the machinability are better considered, the scrape resistance is substantially improved, and the ionomer modified polypropylene composite material is suitable for manufacturing automobile internal and external decorative parts; the preparing method is simple, easy to implement and low in cost, and it is unnecessary to use a supercritical material.