A liquid-cooled pipe for use in a liquid-cooled heat sink kit is disclosed to include a pipe body, which has a close end, an open end, an axial passage extending from the close end to the open end, and a longitudinal series of through holes in the peripheral wall, a plurality of partition members respectively inserted into the axial passage of the pipe body connected in series with the partition plate of one partition member stopped against the legs of next such that each two adjacent partition members define with the pipe body a respective small chamber in fluid communication with two through holes of the pipe body, and an end cover plate fixedly fastened to the pipe body to seal the open end.