A method of manufacturing a printhead for raising its product acceptance rate and improving its quality is provided. The method of manufacturing printheads includes steps of providing a base layer, forming a pattern layer on the base layer by a semi-conductor manufacturing process, forming a dry film of a channel barrier layer having an ink channel, a flow channel and plural ink cavities on the pattern layer; and adhering a nozzle plate on the dry film of the channel barrier layer by thermal compression. The pattern layer further includes a flow pattern and a base pattern surround a central location reserved for the ink channel, wherein the base pattern comprises at least a heating layer and a passivation layer, and the flow pattern is made of the same material and at the same height as the base pattern.