A heat-dissipating fan includes a housing, a stator, a rotor and at least one retaining member. The stator and rotor are received inside the housing. The rotor includes an impeller having a plurality of blades. The at least one retaining member is removably mounted to the housing and includes a retaining plate. In an axial direction of the rotor, the retaining plate extends to be above and within a rotational area of the blades to retain the rotor to avoid departure of the rotor from the housing, even if the heat-dissipating fan is hit hard while it is packed, moved, transported or operating. Besides, the arrangement of the retaining member won't result in reduction of air input. Consequently, the retaining member can be quickly mounted to the housing at a predetermined position to enhance convenience of assembly.