The phase transition, thermal expansion property, sintering property and electrical conductivity of Ba0.6Sr0.4Zr1 -yYyO3 - delta have been investigated. Crystal structure of Ba0.6Sr0.4Zr1 -yYyO3 - delta (0.0 <= y <= 0.2) at room temperature is tetragonally distorted perovskite. The temperature of the second order phase transition from tetragonal to cubic gradually increased with increasing Y content, which affected thermal expansion coefficient. High sintering property was maintained regardless of Y content and Ba0.6Sr0.4Zr1 -yYyO3 - delta showed the highest proton conductivity among Ba0.6Sr0.4Zr1 -yYyO3 - delta (0.0 <= y <= 0.2), which was relatively high among so far reported proton conductivity in BaZr1-xYxO3-delta or SrZr1-xYxO3-delta system. (C) 2011 Elsevier B.V. All rights reserved.