Embodiments of the present invention disclose a portable terminal and a slot antenna thereof, and relate to the field of mobile communications technologies, which can effectively reduce a space occupied by the antenna and at the same time meet various bandwidth requirements. The slot antenna of the portable terminal includes: a large-area conductor plane laid on a printed circuit board, a battery with a bulk conductor, and a first feeding part, where a slot is formed between the conductor plane and the battery, the conductor plane is radio-frequency coupled to the bulk conductor in the battery through the slot, and the first feeding part is located in the slot. The present invention is applied in designing the antenna of the portable terminal.