Polycrystalline bulk Tb0.8Eu0.2MnO3 was prepared by solid phase reaction. The XRD analysis of the sample showed that the Eu3+ had been doped in TbMnO3. Dielectric properties were examined as functions of temperature (100 K ≤T≤ 300 K) and frequency (200 Hz≤ f ≤100 kHz). Two dielectric relaxations were found in these ranges. By means of analysis the low-temperature relaxation was ascribed to the dipolar effects induced by carriers hopping; and the high-temperature relaxation was found to originate from the internal barrier-layer capacitor effects of ion conductivity. The measurement of resistivity showed that there is a marked transition around 230 K, indicating that different conductive mechanisms underlay the transport processes.