Copper indium sulfide (CuInS2) nanocrystalshave the advantages of wide emission spectra, tunable emission wavelength, high quantum yield, low synthesis cost, and easy integration with encapsulation materials. It has broad application prospects in white LEDs with remote configuration. The remote white LED structure is a new type of encapsulation structure proposed for the problem of LED heat dissipation. The composite fluorescent coating (composite film) and the blue chip are encapsulated by a distance in this structure. This structure greatly reduces the requirements for the thermal stability of nanocrystals in the composite film. In this paper, we prepared CuInS2 nanocrystal fluorescent materials with different emission wavelengths, and then the nanocrystals were encapsulated into the PMMA matrix to fabricate a series of CuInS2 nanocrystal/PMMA composite films.Through the methods of fluorescence spectroscopy and ultraviolet-visible absorption spectroscopy, we conducted a detailed study on the red shift of emission wavelength and inconsistent transmittance of nanocrystal/PMMA composite films.