The green color-converted materials are the core components of laser projection display. To date, the high-performance narrowband green color-converted materials for high-quality laser display are still in short supply. In this paper, the commercial narrowband green-emissive β-SiAlON∶Eu²⁺ phosphor together with a kind of low-melting-glass of new composition are co-sintered on a high thermal conductivity sapphire substrate coated by one-dimensional photonic crystal film, forming an integrated phosphor-in-glass film composite. It is demonstrated that the thermal erosion of β-SiAlON∶Eu²⁺ is insignificant after low temperature co-sintering. The composite material exhibits the internal quantum efficiency of 55%, full width at half maximum of 54 nm, and excellent resistance to thermal quenching (the integral luminescence intensity at 150 ℃ remains about 90% of that at room temperature). It is also found that the one-dimensional photonic crystal film greatly enhances the forward green luminescence up to about 1.5 times. The luminescence saturation takes place under 9 W/mm² blue laser irradiation with the corresponding luminous flux of 492 lm, and the latent luminescence saturation mechanism is tentatively analyzed. After coupling with red laser diodes, the color gamut reaches 95.6% NTSC.