A thermal module and a projector using the same are provided. The thermal module comprises a heat sink and a base. The heat sink comprises a bottom, a plurality of fins, a cover, and a plurality of side walls. The fins are disposed on the bottom, and each of the fins comprises a reference plane and a plurality of protrusions, wherein adjacent two of the protrusions are convex toward opposite directions with respect to the reference plane, and rows of through holes are formed by adjacent two protrusions along a flowing direction. The cover is disposed on the fins. The side walls are disposed between the bottom and the cover and surrounding the fins, wherein a liquid is capable of flowing through the heat sink by entering the inlet and exiting by the outlet of the side walls or the cover. The bottom of the heat sink is disposed on the base.