A heat dissipation device includes a retention module surrounding a heat-generating component therein and a heat sink secured in the retention module. The retention module has a plurality of sidewalls. The heat sink includes a base positioned in the retention module for contacting with the heat-generating component. The base includes a plurality of first walls and a plurality of second walls. The sidewalls of the retention module enclose a periphery of the base, and the first walls and the second walls respectively abut against the sidewalls of the retention module when the base is located at a first position and a second position. A rotation of the base from the first position to the second position reduces an adhering force generated by a thermal grease located between the base and the heat-generating component.