  Similar to the superradiant effect in Reissner-Nordstr\"{o}m black hole, a
charged scalar field can be amplified when impinging on the charged black hole
in string theory. According to the black-hole bomb mechanism,the mass term of
the incident field can works as the reflecting mirror, which may trigger the
instability of black hole. We study the possible instability triggered by
superradiant effect and demonstrate that the charged black hole in string
theory is stable against the massive charged scalar perturbation. The reason is
that there is no trapping potential well in the black hole exterior which is
separated from the horizon by a potential barrier and there is no bound states
in the superradiant regime.
