A liquid heat-dissipating assembly has a heat-guiding tube assembly, multiple heat-dissipating units, and at least one heat-dissipating tube. The heat-guiding tube assembly has a first tube, a second tube, and a separating segment. The first tube has at least one first channel. The second tube has at least one second channel. The separating segment is mounted between the first tube and the second tube. The heat-dissipating units are connected with the heat-guiding tube assembly, and each heat-dissipating unit has a heat-dissipating body, a first pipe, and a second pipe. The heat-dissipating body has a passage. The first pipe is connected with the passage and the at least one first channel. The second pipe is connected with the passage and the at least one second channel. The at least one heat-dissipating tube is connected with the at least one second channel of the second tube.