Abstract: A portable water purifier has a container, a lid assembly, and a filtering assembly. The container has a containing space. The lid assembly is mounted to the container by threading and has a suction nozzle communicating with the containing space. The filtering assembly is mounted in the container, is connected to the lid assembly, and has a cover and at least one filter element. The cover is disposed in the container, is adjacent to the lid assembly, and has a communicating tube communicating with the suction nozzle and an interior of the container. The at least one filter element is disposed between the cover and a bottom of the container.