The brickwallmodelwas used to directly calculate the Boson entropy of scalar field in the
background of1+1 dimensional(space-time) black holes. The results show that the entropy is related
to both the outer and innerhorizons. If the contribution of the innerhorizon is considered, the entropy
approaches zero as the radiation temperature approaches zero. The entropy satisfies the Nernst
theorem, so itcan be regarded asPlank absolute entropy. If the contribution of the innerhorizon isnot
considered, the entropy has a logarithmically divergent term, which is the same with the known
conclusion.