The oxygen storage capacity (OSC) and oxidation-reduction properties of CuCr1-xAlxO2 with the delafossite-type structure were investigated. Solid solutions with the delafossite-type structure were synthesized by a solid-state reaction route at 1100-1150 degrees C in N-2 atmosphere. The substitution of Al3+ for Cr3+ in CuCrO2 suppressed OSC and enhanced its stability to heat treatments under cyclic oxidative/reductive atmosphere. Under 5% H-2/He atmosphere, the delafossite phase was reduced to a mixture containing Cu and a corundum-type Cr2O3 solid solution (x = 0-0.3). In the region with x = 0.5-0.9, metallic Cu and delafossite phase coexisted. Following repetitive reduction by H-2-pulse injection, a transition alumina phase was detected. The transformation between delafossite- and spinel-type structures can occur without significant diffusion of atoms, and therefore, the cyclic oxidation/reduction of CuCr1-xAlxO2 delafossite is reversible. These results suggested that the reduction of CuCr1-xAlxO2 is the key step in the reversible oxygen storage/release process.