We propose use of a liquid phase deposition method (LPD) to prepare the composite ceramics with no chemical reaction between the two phases. Mg₂SiO₄–TiO₂ composite ceramics is desirable for microwave/millimeter-wave dielectric devices, because the appending TiO₂ into Mg₂SiO₄ improves the temperature coefficient of resonant frequency (τ_f) to 0 ppm/°C. However, there is a problem that the secondary phases: MgSiO₃ and MgTi₂O₅ are created during sintering at elevated temperatures. The presence of the secondary phase results in decrease of the quality factor (Q·f). To prevent the production of the secondary phase, we try to investigate another route to prepare the Mg₂SiO₄–TiO₂ composite ceramics using a liquid phase deposition (LPD) process as follows: Porous Mg₂SiO₄ ceramics were prepared by sintering Mg₂SiO₄ with pore-forming agents. Then, TiO₂ was deposited into the pores using LPD. In particular, this study focused on two conditions to deposit TiO₂ in porous Mg₂SiO₄: (1) the firing temperature after depositing TiO₂ in the porous Mg₂SiO₄ and (2) the concentration of the precursor solution for the LPD.