A temperature-controlling measure for a hydrogenation slurry bed reactor has three control points that are set from low to high: cold hydrogen is injected automatically when the system reaches control point 1; cold oil is injected automatically when the system reaches control point 2; each pressure relief is opened automatically when the system reaches control point 3. The pressure relief point is set before and/or after the circulation pump of the reactor if internal circulation is set in the reactor; the pressure relief point is set at the reactor bottom if the internal circulation is not set; at least one pressure relief valve is set at each pressure relief point.