The present invention is related to a photo bio-reacting system. The photo bio-reacting system comprises a plurality of photo-reacting cultivating modules, each of the photo-reacting cultivating modules having a top portion, a bottom portion and a first portion between the top and bottom portions, the inside diameter of the first portion being less than those of the top and bottom portions, and each of the photo-reacting cultivating modules being pervious to light and a light-emitting module, the light-emitting module emitting light with a predetermined wavelength which irradiates and penetrates each of the photo-reacting cultivating modules.
