The SiI 6560.58{AA} line in the H{alpha} blue wing is blended with a telluric absorption line from water vapor in ground-based observations. Recent observations with the space-based telescope CHASE provide a new window to study this line. We aim to study the SiI line statistically and to explore possible diagnostics. We select three scannings in the CHASE observations, and measure the equivalent width (EW) and the full width at half maximum (FWHM) for each pixel on the solar disk. We then calculate the theoretical EW and FWHM from the VALC model. An active region is also studied in particular for difference in the quiet Sun and the sunspots. The SiI line is formed at the bottom of the photosphere. The EW of this line increases from the disk center to mu=0.2, and then decreases toward the solar limb, while the FWHM shows a monotonically increasing trend. Theoretically predicted EW agrees well with observations, while the predicted FWHM is far smaller due to the absence of unresolved turbulence in models. The macroturbulent velocity is estimated to be 2.80km/s at the disk center, and increases to 3.52km/s at mu=0.2. We do not find any response to flare heating in current observations. Doppler shifts and line widths of the SiI 6560.58{AA} and FeI 6569.21{AA} lines can be used to study the mass flows and turbulence of the different photospheric layers. The SiI line has good potentials to diagnose the dynamics and energy transport in the photosphere.