The invention discloses an inner-glow decorative glass rib system for a glass curtain wall. The system comprises two symmetrically arranged mullions, a glass rib plate and a lamp, wherein at least two hanging shafts are arranged between the two mullions and are arranged in the vertical direction, two ends of each hanging shaft are connected and fixed with the corresponding mullion respectively, hanging pieces correspondingly matched with the hanging shafts are arranged at one end of the glass rib plate, one end, where the hanging pieces are arranged, of the glass rib plate is located between the two mullions and hung on the corresponding hanging shafts through the hanging pieces, and the lamp is arranged between the two mullions and illuminates the glass rib plate through the end surface of the glass rib plate. The lamp is hidden between the two symmetrically arranged mullions, and lamp light illuminates the glass rib through the end surface of the glass rib, so that the inner-glow effect of the glass rib is realized; compared with the conventional scheme that the side surface of the glass rib is illuminated from outside, the system has a better effect, the external overall effect of the glass curtain wall cannot be influenced, the lamp can be mounted and replaced indoors, and the system is more convenient and safer.