A thermal grease smearing apparatus includes a platform for placing a heat sink, a supporting post projecting from the platform, and a bracket mounted to the supporting post. The bracket includes a bottom plate with a smearing hole. A thermal grease pipe is mounted to the bracket and includes a pipe body having an upper opening for introducing thermal grease and a lower opening for applying the thermal grease onto a bottom surface of the heat sink. When the bracket is positioned in a working position, the bottom surface aligns with a the smearing hole and abuts a lower surface of the bottom plate, a smearing portion contacts with the thermal grease applied onto the bottom surface and is actuated to rotate about a central axis of the thermal grease pipe thereby smearing the thermal grease uniformly spread on the bottom surface of the heat sink.