The black talc powder was surface-modified using different ratios of sodium dodecyl sulfate and polyethylene glycol 300. The modified black talc powder was then used to prepare black talc/polypropylene (PP) composite materials with a filler content of 25%. The oil absorption value and sedimentation volume of the black talc powder before and after modification, and the mechanical properties of the composite materials were tested. The microstructure of the fracture surfaces of the black talc powder and composite materials before and after treatment was also examined. The results showed that the black talc powder modified with a modifier having a mass ratio of sodium dodecyl sulfate to polyethylene glycol 300 of 3∶7 had better dispersibility, lower oil absorption value, and smaller sedimentation volume. Compared with the unmodified powder, the oil absorption value was reduced by 9.6 g/100 g, with a reduction rate of 37.1%, and the sedimentation volume was decreased by 1.9 mL/g.Mechanical property studies indicated that compared with the unmodified composite materials, the black talc powder modified with the compound modifier had better compatibility with polypropylene and more uniform dispersion. The tensile strength, flexural strength, impact strength, and flexural modulus of the E/PP composite materials were significantly increased by 4.25 MPa, 6.74 MPa, 7.17 kJ/m², and 458.89 MPa, respectively.