Side chain type polyethers were synthesized by ring opening polymerization of glycidyl ether with p-alkoxyphenyl moiety. A liquid crystalline phase was found at the alkoxy chain length of below 12. A smectic phase was induced for the mixture of the non-mesomorphic polyethers with alkali metal salt, and the mesomorphic temperature range for the mixed system of the polyethers became wider with increasing amounts of alkali metal salt. These mixtures had ionic conductivity. The ionic conductivity of the mesomorphic polyethers with alkali metal salt was larger than that of the non-mesomorphic polyethers with same alkali metal concentration in the whole measured temperature range. Activation energy of the smectic phase region was larger than that of the isotropic phase region. The ionic conductivity of the liquid crystalline polyether with LiClO4was 5.3 8×10−6Scm−1and that of the non-mesomorphic polyether was 4.57×10−7Scm−1at 100°C.