A color film substrate, a fabrication method therefor, and a display device. The color film substrate comprises a base substrate (1); a black matrix (2) is located on one side of the base substrate (1), the black matrix (2) having a plurality of pixel openings (21); a quantum dot color film layer (31, 32, 33) is located in the pixel openings (21) and comprises an ultraviolet light-curable quantum dot material; and a light conversion structure (4), which is located between a side wall of the black matrix (2) and a side wall of the quantum dot color film layer (31, 32, 33). When a quantum dot solution is UV cured, the light conversion structure (4) may convert ultraviolet light of 395 nm into ultraviolet light that has a shorter wavelength and higher energy. Since the light conversion structure (4) is arranged between the side wall of the black matrix (2) and the side wall of the quantum dot color film layer (31, 32, 33), the ultraviolet light that has a shorter wavelength and higher energy may be emitted from a side edge and irradiated to the quantum dot color film layer (31, 32, 33), which solves the problem of uneven UV curing of the quantum dot color film layer (31, 32, 33), thereby improving the light-emitting performance of the display device.