ZrN_1−x (x = 0–0.3) ceramics with different nitrogen vacancy concentrations were prepared by using reactive spark plasma sintering, with ZrN and ZrH₂ powders as raw materials. With increasing concentration of nitrogen vacancy from 0 to 0.3, relative density of the samples sintered at 1600 ℃ increased from 90.5% to 99.6%, while the second phase of ZrO₂ gradually dissolved into the matrix, the oxygen content of the matrix phase increased from 0.03 at.% to 10.04 at.%, the average grain size increased from 3.12 μm to 33.13 μm and the lattice constant first increased and then decreased. The lattice constants of ZrN_1.0, ZrN_0.9, ZrN_0.8 and ZrN_0.7 are 4.5769 Å, 4.5806 Å, 4.5834 Å and 4.5799 Å, respectively. The Young's modulus of ZrN_1−x decreased gradually with increasing concentration of nitrogen vacancy, while the Young's modulus of ZrN_1.0-1700 and ZrN_0.7-1600 with similar relative density were 365 GPa and 300 GPa, respectively. The experimental lattice constant and Young's modulus are consistent with the first-principles calculations results.