Effects of ferroelectric BaTiO3 particles were investigated on the dielectric behavior of BaTiO3–Ni–polymethyl methacrylate composites fabricated by a two-step mixing and hot-molding method. The percolation power law in the smearing region was employed to explain the experimental results. The composites exhibit the dependence of the dielectric constant, dielectric loss, and percolation threshold on the concentration and particle size of BaTiO3. The results suggest that BaTiO3 particles play an important role in increasing the percolation threshold and the smearing region as well as the dielectric constant of BaTiO3–Ni–polymethyl methacrylate composites.