Disclosed is a top surface wave antenna of a spherical Tokamak, comprising a feedback waveguide, a brim, sub-waveguides, and a metal base. The lower end of the feed waveguide is connected to one end of the metal base, and one side of the feed waveguide is connected to the brim. The brim is towards a length direction of the metal base. A plurality of sub-waveguides are arranged on the metal base at equal intervals, the tops of the sub-waveguides are not higher than the height of the metal base, and the sub-waveguides are arranged in a rising line trend. The feed waveguide serves as a microwave input port. The top surface wave antenna of the spherical Tokamak is mainly used in a high-power Tokamak system and acts on the low-hybrid wave current driving together with an external antenna so as to obtain a better effect.