  We report a feasibility study of $CP$ violation of $\tau^{-}\rightarrow
K_{S}\pi^{-} \nu_{\tau}$ decay at a Super Tau Charm Facility~(STCF).With an
expected luminosity of 1~ab$^{-1}$ collected by STCF per year at a
center-of-mass energy of 4.26 GeV, the statistical sensitivity for the $CP$
violation is determined to be of order $9.7\times10^{-4}$ by measuring the
decay-rate difference between $\tau^{+}\rightarrow
K_{S}\pi^{+}\bar{\nu}_{\tau}$ and $\tau^{-}\rightarrow K_{S}\pi^{-}
\nu_{\tau}$. The analysis is performed using a reliable fast simulation
software package, which can describe the detector responses properly and vary
the responses flexibly for further optimization. Moreover, the energy-dependent
efficiencies for reconstructing $\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$
are presented and the expected $CP$ sensitivity is proportional to
$1/\sqrt{\mathcal{L}}$ in the energy region from 4.0 to 5.0 GeV. The
sensitivity of $CP$ violation is of order $3.1\times10^{-4}$ with 10~ab$^{-1}$
integrated luminosity, which is equivalent to ten years data taking in this
energy region at STCF.
