A heat dissipating device includes a box, a flow dispersion layer, a heat exchange layer, a fan and a pump, wherein the box includes a liquid storage part, a liquid-air mixing part, a liquid inlet, a liquid outlet, an air inlet and an air outlet, the flow dispersion layer is disposed in liquid-air mixing part and has a plurality of through holes, the heat exchange layer is disposed in liquid-air mixing part and has a continuous phase framework and pores, the fan is connected to the air inlet, and the pump is connected to the liquid outlet. The heat dissipating device forcibly disperses high temperature liquid, and prolongs falling time of the high temperature liquid, to allow low temperature air directly exchange heat with the high temperature liquid, so that the heat dissipation efficiency thereof is greatly enhanced to meet the demands of electronics, air conditioning and other industries.