A circuit substrate ready to slot is revealed, primarily comprising a board base with slot-reserved area. A plurality of bonding fingers, a plating bus loop, and a plurality of plating lines disposed on the bottom surface of the board base. The bonding fingers are located adjacent to but outside the slot-reserved area and the plating bus loop is located inside the slot-reserved area. The plating lines connect the bonding fingers to the plating bus lines. The plating bus loop includes two side bars closer to the long sides of the slot-reserved area than the bonding fingers to the long sides. Accordingly, the lengths of the plating lines within the slot-reserved area are shortened. It is possible to solve the issues of metal burs and shifting of the remaining plating lines when routing a slot along the peripheries of the slot-reserved area. Moreover, the plating current can evenly distribute to improve the plating qualities on the surfaces of the bonding fingers.