A container data center includes a container and a server cabinet received in the container. The server cabinet includes a rack and a number of heat dissipation devices mounted to a rear side of the rack. Each heat dissipation device includes a case fixed to the rack, a fan mounted to an outer side of the case, and a heat dissipation plate received in the case and aligning with the fan. The heat dissipation plate defines a vent. The fan draws heat air through the vent of the heat dissipation plate from the rack, and the heat air is cooled by refrigerant received in the heat dissipation plate to become cool air. The cool air flows in the container, and circularly flows into the cabinet from a front side of the cabinet.