Molecular dynamics simulation was performed in order to design a new perovskite oxygen ion conductor. The results suggested that (Sm(1-x)A(x))AlO3-x/2 (A=Ca or Sr) exhibits relatively high conductivity. Based on this result, (Sm1-xCax)AlO3-x/2 (x=0.1-0.22) compounds were synthesized to investigate the properties of oxygen ion conduction. The conductivity obtained quantitatively agreed with the calculated value at each Ca concentration. In this system, (Sm0.8Ca0.2)AlO2.9 had the highest conductivity of 0.037 S/cm at 800degreesC with an ionic transference number of 0.96. (C) 2003 Elsevier Science B.V. All rights reserved.