This disclosure relates to an external liquid cooling device including at least one radiator, at least one airflow generator, a water block and a mount head module. The at least one airflow generator and the water block are respectively disposed at two adjacent sides of the at least one radiator. The mount head module includes two connectors which are respectively connected to the at least one radiator and the water block via piping. The mount head module and the water block are respectively located at two opposite sides of the at least one radiator.