A liquid cooling heat dissipation device includes a heat-dissipating module and a liquid supply module. The liquid supply module includes an outer cover body disposed on the heat-dissipating module and at least one pump disposed inside the outer cover body. The outer cover body has an inner space divided into a first independent space adjacent to the heat-dissipating module and a second independent space far away from the heat-dissipating module and insulated from the first independent space, the at least one pump includes a stator disposed inside the first independent space and a rotator disposed inside the second independent space, and the stator is closer to the heat-dissipating module than the rotator. The instant disclosure further provides an electronic device using the liquid cooling heat dissipation device.