  This paper deals with the semiclassical radiation spectrum of static and
circularly symmetric 3D charged dilaton black holes with cosmological constant
{\Lambda} in non-asymptotically flat spacetimes. We first review the 3D charged
dilaton black holes which are solution to low-energy string action. The wave
equation of a massless scalar field is shown to be exactly solvable in terms of
hypergeometric functions. Thus, the radiation spectrum and its corresponding
temperature are obtained, precisely. Computations at high frequency regime show
that the radiation spectrum yields the Hawking temperature of the black hole
with no charge. Unlike the chargeless case, the Hawking temperature of the
charged dilaton black holes is derived from the radiation spectrum at the low
frequencies. The utmost importance of the {\Lambda} in the latter result is
highlighted.
