The elastic properties and optic characteristics of shocked Z-cut quartz were carefully examined，by using symmetric plate impact and in situ measurement. Results show that Z-cut quartz exhibits a simple-wave elastic response and keeps transparent up to a pressure of no less than 10 GPa，and it can be used as the opical window for velocity measurement within this pressure range. The relation of elastic shock wave velocity and particle velocity satisfies linear function very well. On the other hand，the velocity correction of Z-cut quartz at incident laser wavelength of 1550 nm can be better represented by exponential function than linear one，while the relation between refractive index and density of Z-cut quartz at 1550 nm satisfies the linear function very well. The results in this paper lay a foundation for using Z-cut quartz as optical windows of interferometer systems working with laser at 1550 nm wavelength.