The invention discloses a kind of preparation method of the titanate KR-38S surface modified minicrystal muscovite active fille and chooses muscovite as raw material. The technics is as follows: weigh minicrystal muscovite and then put it into high-speed mizer; heat the material, whisk it in the high-speed mixer for 30 minutes and adjust the temperature no higher than 90deg.C; weigh the thinner of titanate, acetone, in amounts of weight, titanate:acetone=1:1-3; weigh titanate KR-38S, material: titanate=100:0.4-3.9; confect the titanate surface modified solution, put the titanate into the container with thinner of acetone and whisk it until being well-proportioned; mix the material in high gear, put the titanate surface modified solution into the high-speed mixer and whisk it for between 10min and 30min and control the temperature no more than 90deg.C. It is featured by abundant resource, low cost, convenient technics, wide use and obvious economic and social effects.