Power monitor device and its method for use in a computer apparatus

The present invention discloses a power monitor device for use in a computer apparatus, which comprises a heat sink module, a level sensor and a power control unit. The heat sink module is installed in a heating unit of the computer apparatus, and contains cooling fluid, so as to process a heat dissipation procedure to the heating unit. The level sensor is coupled to the heat sink module for calculating a fluid residual value according to the residual fluid of the heat sink module. The power control unit is coupled to the level sensor and the computer apparatus for simultaneously turning off the power of the heat sink module and the computer apparatus when the fluid residual value is lower than a system predetermined value, so as to avoid damages of data or other electronic components when the computer is suddenly shut down due to the overheat of the heating unit.