A liquid dispenser, comprising a liquid dispenser shell (1) that is provided with a cavity (11); one liquid inlet hole (12) and a plurality of liquid outlet holes (13) that are provided on the liquid dispenser shell (1), the liquid inlet hole (12) and the liquid outlet holes (13) both being in communication with the cavity (11); and positioning members (15), the positioning members (15) being disposed on the liquid dispenser shell (1), and the positioning members (15) being configured to allow the liquid dispenser and a porous plate for liquid dispensation to be positioned and matched with each other.