A method for manufacturing an ink-jet printhead by coating a first photosensitive photoresist on the substrate and forming a passage plate, forming an ink chamber and an ink passage on the passage plate, burying the ink chamber and the ink passage using a second photoresist and forming a mold layer, forming a chamber cover layer on a top surface of the passage plate and the mold layer, forming a plurality of slots corresponding to the ink chamber and/or the ink passage in the chamber cover layer, supplying an etchant to the second photoresist through the slots and removing the second photoresist remaining in the ink chamber and the ink passage, and coating a third photoresist and forming a nozzle plate on the chamber cover layer.