Abstract: A coolant flow guide for grinder includes a base including a tilted bottom wall having a predetermined tilt angle, a peripheral wall disposed around the tilted bottom wall and defining with the tilted bottom wall a diversion channel having a top opening and a partition wall located on the tilted bottom wall to divide the diversion channel into two flow passages that slope downwardly to the diversion port, and a workpiece positioning unit mounted on the base above the flow passages for holding a workpiece. Thus, when the grinder is operated to grind the workpiece, the debris thus produced is carried by the applied coolant to flow through the flow passages to the outside of the base via the diversion port.