New microwave dielectric ceramics of LiZnSbO₄ were prepared by the reactive sintering method. Within the sintering temperature zone of 1350^∘C–1385^∘C,a single-phase LiZnSbO₄ with an orthorhombic structure was identified by XRD refinement,which contains 10 molecular formula per unit cell (i.e.,$Z=10$). The relative density and average grain size had a main effect on ${\epsilon }_r$ and $Q\times f$ value of the LiZnSbO₄ ceramics,whereas the phase assemblage was responsible for its ${\tau }_f$. The 1375^∘C-sintered LiZnSbO₄ specimens owned comparable low ${\epsilon }_r\sim 6.5$,but ultra-high $Q\times f\sim 74,500$$$GHz (nearly three times) compared to LiZnPO₄ and LiZnVO₄ ultra-high $Q\times f\sim 74,500$$$GHz (nearly three times) compared to LiZnPO₄ and LiZnVO₄ manufactured,which showed a return loss as low as 37.4$$dB,maximum gain of 5.7$$dB and a fractional bandwidth of 3.9% (11.95–12.43$$GHz).