PURPOSE: A silicone grease composition for the heat isolation is provided, which does not generate the void or the crack, and deviation or the oil breed when the composition is exposed to high temperature for a long time. CONSTITUTION: A silicone grease composition for the heat isolation includes: 100 weight parts of an organopolysiloxane which has the thixo drawing alpha of 1.03-1.50, viscosity of 100-1,000,000mPa·s at 25°C as a component; 5-200 weight parts of a hydrolyzable organopolysiloxane of one side end three organic functions as component; and 200-4000 weight parts of a thermal conductive inorganic filling having the average particle diameter of 0.1-100 micrometers and the specific surface area of 0.01-50m^2/g as component.