Abstract: A detachable guide air hood, which fits with a fan frame for enhancing heat dissipation, includes a hollow guide air bucket, a fitting part and at least a pair of holding hooks. The hollow guide air bucket provides a large opening and a small opening with two opposite first inclined side walls and two opposite second inclined side walls having a shape of convergence from the large opening to the small opening. The fitting part is disposed at the small opening and provides two opposite first parallel side walls and two opposite second parallel side walls. The parallel side walls are joined to the guide air bucket. The holding hooks are disposed at the joint of the guide air bucket and the fitting part and an end of the respective holding hook is connected to the guide air bucket.