Inorganic perovskite quantum dots (P-QDs) is a new kind of optoelectronic materials in recent years. Because the high quantum yield (QY), the narrow full width at half-maximum (FWHM) and spectrum tenability of novel P-QDs, making them have more potential on the display application. However, P-QDs not only have poor water resistance and heat resistance, but also easily exchange halogen ions to cause wavelength variations. Therefore, the above problems must be solved before use. In this study, red and green P-QDs were synthesized by thermal injection method and then mixed with polymethyl methacrylate (PMMA) in different ratios. Controlling the P-QD concentrations and the thickness of the fluorescent films to form white light. The results show that the fluorescent film can avoid the ion exchange reaction effectively. Moreover, the CIE of P-QD/PMMA device locates at (0.29, 0.31), and the NTSC and sRGB are 131 and 183 %, respectively.