By using plate impact and laser interferometry technology, careful experiments and theoretical analysis for 100 LiF are carried out for its dynamic mechanical response and optical characteristics under shock pressures up to 40 GPa. The accurate shock Hugoniot relation and velocity correction at 1550 nm wavelength are then obtained. Moreover, the direct wave-profile measurments show that LiF keeps an obvious elastic-plastic response within 20.3 GPa, and the estimated lower limit pressure for single-wave shock response is about 2223 GPa. The strength influence of LiF window on the dynamic behavior of the sample should be taken into account in precise experiments with shock pressure lower than this range. The results above establish foundations for the design and data post-processing of shock experiments in which LiF is used as an optical window for the dynamic material properties such as elasto-plasticity, phase transition and melting.