Pure phase Y₃Fe₅O₁₂ (YIG) ceramic was successfully produced by tape-casting forming process and one-step solid-state sintering method. The activation energy for densification was calculated to be 183.81 kJ/mol. Pure YIG ceramic with a relative density as high as 99.8% was fabricated. The existence of O vacancy and Fe²⁺ ions was determined by XPS and EPR spectra. The RT saturation magnetization was measured to be 28.2 emu/g, and the hysteresis loss was calculated to be smaller than 10 mJ/kg in the temperature range of 230～360 K and be as high as 238.8 mJ/kg at 30 K. The dielectric loss tangent tanδε was nearly zero at 6～7 GHz and 11～12 GHz. For complex permeability in the frequency range of 5～18 GHz, the magnetic loss tangent tanδμ  fluctuated at around zero. Therefore, the low values of tanδε and tanδμ indicate that it is a low loss ceramic material.