  The finite temperature effect is examined in Randall-Sundrum brane-world
scenario with inclusion of the matter fields on the brane. At zero temperature
it is found that the theory on the brane is conformally invariant, which
guarantees $AdS$/CFT. At 4d effective action we derived a temperature-dependent
nonvanishing cosmological constant at the flat spacetime limit of brane
worldvolume. At the cosmological temperature $3 {\bf K}$ the cosmological
constant is roughly $(0.0004 eV)^4$ which is within the upper bound of the
recent experimental value $(0.01 eV)^4$
