The utility model relates to the field of optical system design, and particularly relates to a guiding optical device of an emission spectrometric analysis in copper smelting process. The guiding optical device includes a lens, a planar mirror, and a reflector which are arranged in a lens barrel, the lens is arranged at the front section or the middle section of the lens barrel, light enters from the front end of the lens barrel, the planar mirror is arranged at the rear end of the lens barrel, the planar mirror reflects the light collected via the lens to one side of the lens, one side, close to the planar mirror, of the lens or the reflector adjacent to the periphery of the lens is used for receiving the light reflected by the planar mirror, and the lens barrel wall at a position corresponding to the reflector is provided with a through hole for arranging an optical fiber. Incident light is focused on the optical fiber to be output after successively passing through the lens, the planar mirror, and the reflector, and the length of the lens barrel and the energy loss can be reduced through the ingenious arrangement of the positions of the lenses.