The invention discloses a grease collecting device of a dynamometer. The grease collecting device of the dynamometer comprises the components of a grease collecting ring which is annular and is arranged at the outer ring position of the grease that is thrown from a bearing; and fixing boards which are arranged at two sides of the top of the grease collecting ring in pairs and are used for fixing the grease collecting ring to the head portion of a bearing cap fixing bolt. The grease collecting ring of the grease collecting device of the dynamometer is just arranged at the outer ring of throwing-out positions of the grease from the bearing. When the grease is thrown out in high speed, the grease is blocked by the inner wall of the grease collecting ring, so that the grease is collected on the inner wall of the grease collecting ring, thereby realizing a purpose of collecting the thrown-out grease, and preventing unsafe factors, equipment pollution and wall pollution caused by grease throwing-out.