A detailed analysis on the activity-rotation relation for G-type and F-type stars. It shows that the saturation regime has disappeared and the unsaturation regime still follows a law of exponential decay, indicating that C stars become sensitive to temperature, while I stars always follow the same law. Blue dashed lines of left panels separate flare stars into bins by the flare activity. In each bin, the distribution of flare stars along the Rossby number is plotted in right panels. Each distribution is fitted by a Gaussian function that is plotted by a green dashed line. The centers of some Gaussian functions and the average activities of corresponding bins are applied to fit the activity–rotation relation, which is plotted as the green solid line in the left panel. Its slope is marked as β.