  We calculate one-loop R-parity-violating couplings corrections to the
processes $H^-\to \tau\bar{\nu_\tau}$ and $H^-\to b\bar{t}$. We find that the
corrections to the $H^-\to \tau\bar{\nu_\tau}$ decay mode are generally about
0.1%, and can be negligible. But the corrections to the $H^-\to b\bar{t}$ decay
mode can reach a few percent for the favored parameters.
