Abstract: In order to evaluate the stability and durability of zirconia composite ceramics in clinical applications and ensure a strong bond between the restorative and natural teeth, this study used tetragonal zirconia ceramic (3Y-ZrO₂) was used as the matrix material, combined with different mass fraction of lanthanum phosphate (LaPO₄) and different mass fraction of stabilizer Y₂O₃ to prepare the zirconia composite ceramic 3Y-ZrO₂-LaPO₄ for oral restoration. After hydrofluoric acid treatment, the ceramic was bonded to dentin to obtain 3Y-ZrO₂-LaPO₄ bonded samples. By changing the contents of LaPO₄, Y₂O₃ and hydrofluoric acid as well as the sintering temperature, the adhesive strength and microstructure changes of the 3Y-ZrO₂-LaPO₄ bonded samples were investigated. The experimental results show that the adhesive strength of the samples increas with the increase of Y₂O₃ mass fraction from 0 to 4% but decreased slightly when the mass fraction further increased to 6%. The increase of LaPO₄ mass fraction can improve the adhesive strength of the samples, and the adhesive strength reached the maximum when the mass fraction of LaPO₄ was 35% and that of Y₂O₃ was 4%. Hydrofluoric acid treatment has a significant effect on the adhesive strength, with the best effect at the concentration of 10%. Scanning electron microscopy (SEM) observation shows that the increase of Y₂O₃ content improved the density and interfacial bonding strength of the samples, and hydrofluoric acid treatment altered the microstructure of the sample surface. X-ray diffraction (XRD) analysis indicated that the sintering temperature had a significant effect on the crystal phase composition of the samples, and high temperature promoted the crystal phase transformation of zirconia.