Provided is a thermally-curable heat-conductive silicone grease composition which has a high shape-retaining property in an early stage even when the viscosity of the composition is low (i.e., the composition is easy to apply) in the early stage, and which becomes soft (has low hardness) after being cured. A thermally-curable heat-conductive silicone grease composition comprising, as essential components: (A) an organopolysiloxane having a viscosity of 100 to 100,000 mPa·s at 25° C. and containing at least one alkenyl group per molecule; (B) an organopolysiloxane represented by general formula (1) (wherein R1 represents a monovalent hydrocarbon group; R2 represents an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group; n represents 2 to 100; and a represents 1 to 3); (C) an organohydrogenpolysiloxane containing at least two hydrogen atoms each directly bound to a silicon atom per molecule; (D) a catalyst selected from the group consisting of platinum and platinum compounds; (F) a heat-conductive filler having a heat conductivity of 10 W/m·° C. or more; and (G) a silica micropowder.