Na-ion batteries, which currently use flammable and explosive organic electrolytes, now urgently need to develop high performance sodium ion solid electrolyte to realize more safe and practical application. Na₃Zr₂Si₂PO₁₂ is one of the most promising solid sodium electrolytes for its wide electrochemical window, high mechanical strength, superior air stability and high ionic conductivity. But its inhomogeneous mixing of the ceramic particles with the binders causing much more pores in the green bodies makes it difficult to obtain high-density and high-conductivity ceramic electrolytes after sintering. Herein, the spray drying method was used to enable Na₃Zr₂Si₂PO₁₂ particles uniformly coated with binders and granulated into spherical secondary ones. The as-prepared normal distributed particles can effectively contact each other and reduce porosity of ceramic green body. After sintering, Na₃Zr₂Si₂PO₁₂ ceramic pellets via the spray drying show relative density of 97.5% and ionic conductivity of 6.96×10^-4 S∙cm^-1 at room temperature. In contrast, the relative density and room-temperature ionic-conductivity of Na₃Zr₂Si₂PO₁₂ ceramic pellets prepared without the spray-drying are only 88.1% and 4.94×10^-4 S∙cm^-1, respectively.