The solid solutions of nitridosilicate phosphors LiSi₂N₃:Eu-xAlN (0 ≤ x ≤ 0.35) were synthesized using a gas-pressed sintering in this work. The effects of a solid solution of AlN on crystal structure, morphology, thermal stability and luminescence properties were studied. The luminescence intensity of LiSi₂N₃:Eu phosphor is significantly improved by the solution of AlN, but the emission position is unchanged. The emission intensity of LiSi₂N₃:Eu_0.01-0.30AlN is about 2.17 times that of LiSi₂N₃:Eu_0.01. The results show that these solid solutions could be the most useful way to improve the luminescence intensity of LiSi₂N₃:Eu phosphors.