A water-cooling heat dissipation device includes a water-cooling radiator. The water-cooling radiator includes a radiating pipe unit, a water outlet reservoir, and a water inlet reservoir. The water-cooling radiator is provided with a first water pump and a second water pump. Each water pump is configured to pump cold water in a corresponding water outlet chamber to a corresponding water-cooling block to exchange heat and become hot water, hot water flows back to a corresponding water inlet chamber and flows into the corresponding radiating pipe unit to be cooled by radiating fins, and then cold water flows into the corresponding water outlet chamber.