An airflow guider includes a plate-like member having a stop portion extending transversely, a rear inclined guiding portion extending downward rearward toward a first side from a top edge of the stop portion, a front inclined guiding portion extending slantwise forward toward the first side from the stop portion, and at least one fixture for installing the airflow guider to a heat sink. In light of the structure, the airflow guider can be coordinately installed to various kinds of heat sinks and provide additional thermal dissipation.