The effect of calcium cyanamide (CaCN 2 ) additives on the grain growth and electric properties of liquid phase sintered AlN ceramics have been investigated using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM) attached with an energy dispersive X-ray microanalyzer (EDX) and an inductance-capacitance-resistance (LCR) meter. The grain sizes of the AlN compacts containing 1.5 wt.% CaCN 2 additive and sintered at 1700, 1750 and 1800 o C for 1 h are about 0.35, 0.40 and 0.56 μm, respectively. When the compacts are sintered at 1750 o C for 12 and 6 h, the grain size decreases from 1.20 to 0.87 and 1.06 to 0.80 μm with the CaCN 2 additive content increased from 0.50 to 3.0 wt.%, respectively. The grain size increases from 0.29 to 0.39 μm with the CaCN 2 content increased from 1.0 to 1.5 wt.% when sintered at 1750 o C for 1 h. When the AlN compact containing 1.0 wt.% CaCN 2 additive is sintered at 1750 o C for 6 h, the electric resistance is 5.0x10 1 4 Ω. For the compacts containing 0.50 wt.% CaCN 2 additive and sintered at 1700, 1750 and 1800 o C for 1 h, the electric resistances are 1.6x10 1 4 , 1.4x10 1 4 and 6.3x10 1 3 Ω, respectively. When measured at 1-10 kHz, the relative dielectric constant decreases from 7.0 to 3.5 for the AlN compacts containing 1.0 wt.% CaCN 2 additive and sintered at 1750 o C for 1 h. The relative dielectric constant decreases from 3.5 to 1.4 when the testing frequency is in the range of 10 kHz-1 MHz. The grain size of the sintered AlN compacts with 1.01 wt.% CaCN 2 additive is greater than 0.6 μm and the relative dielectric constant approaches 1.0.