The present application discloses a rotary liquid distributor for a liquid-cooled tank, and a liquid-cooled tank. The rotary liquid distributor includes a liquid distribution cavity and a liquid distribution arm provided in the liquid distribution cavity. The liquid distribution cavity rotates around a central shaft thereof. A plurality of the liquid distribution arms are uniformly distributed in a circumferential direction of the liquid distribution cavity. That is, the liquid distribution arm rotates with the liquid distribution cavity. Then, a liquid distribution outlet is provided between a first end and a second end of the liquid distribution arm. The liquid distribution outlet is located on a side of the liquid distribution arm facing away from a rotating direction.