  We study a false vacuum decay in a two-dimensional black hole spacetime
background. The decay rate in the case that nucleation site locates at a black
hole center has been calculated in the literature. We develop a method for
calculating the decay rate of the false vacuum for a generic nucleation site.
We find that the decay rate becomes larger when the nucleation site is close to
the black hole horizon and coincides with that in Minkowski spacetime when the
nucleation site goes to infinity.
