The invention discloses a discharging electrode used for a capillary extreme ultraviolet photoetching light source, belongs to the technical field of the extreme ultraviolet photoetching light source, and solves the problems of difficulty in satisfying the requirements of plasma length fine tuning and high operational difficulty existing in the extreme ultraviolet generation process by a capillary discharging Z pinching method when a way of replacing the capillaries of different lengths is adopted. The discharging electrode used for the capillary extreme ultraviolet photoetching light source provided by the invention comprises a discharging electrode, a main discharging electrode a locking nut, a pressing ring and a terminal, wherein a pre-discharging electrode adopts a cylindrical structure; a cone is arranged at one end of the main discharging electrode, a cylinder I is arranged in the middle, and a cylinder II is arranged at the other end of the main discharging electrode; the terminal is fixedly arranged in a concave hole which is formed in one bottom surface of the cylinder II through the pressing ring; one bottom surface of the cylinder II is taken as the end plane of one end of the cylinder II, while the other end of the cylinder II is arranged in the cylindrical structure; and the cylinder II and the cylindrical structure are in threaded connection, and are fixed through the locking nut. The discharging electrode provided by the invention is applicable to the capillary extreme ultraviolet photoetching light source.