A cooling fan (100) includes a frame (10), a circuit board (20) and a rotor (30). The frame includes a housing (12) and a plate (14) connecting with the housing. The circuit board is mounted on the plate. The rotor is received in the housing and includes a hollow hub (32) and a plurality of blades (38) extending from the hub. A plurality of light emitting diodes (40) is mounted on the circuit board. When the rotor rotates, each LED projects light towards the rotor and to the frame so that the light will be reflected and deflected by the fan whereby the whole fan glows and produces a fantastic visual effect.