  A detailed analysis on the rare $\tau$ decay {\it via} $\taumue$ and
$\taumus$ in the string models with $\e6$ symmetry is reported. It is found
that $\Gamma(\taumue)\sim(6-7)\Gamma(\taumus)$ and these rates are in general
about 1000 times less than that of $\Gamma(\mu\rightarrow e\gamma)$. It is also
found that the out-going muon in $\taumue$ is almost 100\% right-handed
polarized and the out-going electrons would be predominately parallel to each
other. These decay processes may be accessible at the SSC.
