The Li6Mg7Zr3O16 samples were prepared with the pure cubic phase at sintering temperatures of 1300-1550 °C using the traditional solid state method. Sintering characteristics and microwave properties were investigated as a function of sintering temperature. The samples sintered at 1500 °C showed the best properties of the quality factor (Q·f ) value of 81,284 GHz (at 8.94 GHz), dielectric constant value of 14.22 and the resonant frequency (τf) value of -21.56 ppm/°C. The complex permittivity values of Li6Mg7Zr3O16 ceramic sintered at 1500 °C were characterized by the infrared spectra based on the classical harmonic oscillator model. In order to reduce the sintering temperature, lithium fluoride was used as sintering additives, and then the apparent densities, phase compositions and dielectric properties of Li6Mg7Zr3O16 -x (0 wt% LiF ≤ x ≤ 5 wt% LiF) were discussed as a function of lithium fluoride additives. As a result, the densification temperatures for Li6Mg7Zr3O16-5 wt% LiF were reduced to be 1100 °C, which was significantly lower than that of the matrix (1500 °C). Excellent microwave dielectric properties were obtained in Li6Mg7Zr3O16-5 wt% LiF ceramics sintered at 1100 °C with εr=13.67, Q·f = 132,600 GHz (at 9.26 GHz) and τf = -18.89 ppm/°C.