A multi-band antenna has a grounding plate, a radiating element and a parasitic element. The radiating element has a level radiating portion disposed a predetermined distance away from the grounding plate and a first connecting portion connecting the level radiating portion with the grounding plate. The parasitic element has a substantially L-shaped parasitic portion away from the grounding plate and a second connecting portion disposed at the same side of the grounding plate with the first connecting portion to connect a free end of the L-shaped parasitic portion with the grounding plate. The L-shaped parasitic portion is substantially at the same plane with and spatially fences the level radiating portion to define a substantially L-shaped space. The multi-band antenna has simple structure and small size to be assembled in the limited space of notebook.