Glazes composed of potassium feldspar as main crystals hold promising potential for addressing the issues of insufficient bonding strength and high brittleness in tetragonal zirconia ceramics. The effect of scandium oxide content on structure and characteristics of potassium feldspar crystalline glazes was studied by DSC, XRD, SEM, hardness, strength, refractive index, visible light transmittance and thermal expansion tests. The results indicate that as Sc2O3 content increases from 0% (mass fraction, the same below) to 10%, the crystallization temperature of crystalline glaze decreases from 958.5 ℃ to 827.8 ℃, accompanied by an increase in crystallization capacity. Furthermore, the grain size of sintered crystalline glaze steadily enlarges. With the increase of Sc2O3 content, scandium silicate crystals precipitate within the crystalline glaze. The crystallinity, knoop hardness, bending strength and refractive index of crystalline glaze reach their optimal values at Sc2O3 content of 6.67%. The visible light transmittance decrease first and then increase, while the thermal expansion coefficient decreases.