Ceramic rods of GdBa 2 Cu 3 O 7-δ -based composites with BaAl 2 O 4 and Gd 2 BaCuO 5 were prepared by solid-state reaction. When a certain voltage was applied to the rod, electric current decreased abruptly, and a hot spot appeared. After the appearance of the hot spot, the current remained constant with increasing voltage. The maximum withstanding electric-power for the rods significantly increased upon adding BaAl 2 O 4 and Gd 2 BaCuO 5 . The current after the appearance of the hot spot depended on the oxygen partial pressure in the ambient atmosphere. For the GdBa 2 Cu 3 O 7-δ rod, the current oscillated under low oxygen partial pressure. In contrast, the composite rods showed stable sensing characteristics, which resulted in the improvement of response under low oxygen partial pressure. Compared with the BaAl 2 O 4 -added composite, the Gd 2 BaCuO 5 -added composite rod showed a high durability for sensing applications even in high oxygen partial pressure.All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications Ltd, www.scientific.net.