  In recent years, $B_s$ decays into $tau^+tau^-$ has attracted a lot of
attention since it is very sensitive to the structure of standard model (SM)
and potential source of new physics beyond SM. In this paper, we study the
effect of both Z and -mediated flavor-changing neutral currents on the $B_s$
decays into $tau^+tau^-$. We find the branching ratio of $B_s$ decays into
$tau^+tau^-$ is enhanced relative to SM prediction, which would help to explain
the recent observed CP-violation from like-sign dimuon charge asymmetry in the
B system.
