In this work, the electrochemical discharge capacity of melt-spun (MmY)1 (NiCoMnAl)5 ribbons, in which the content of yttrium was 0-2.5wt%, was studied in the temperature range of 30~80oC. It was found that adding element yttrium made the electrochemical capacity of the compounds increased. The capacity obtained was 333mAh/g at 30 oC and 247 mAh/g at 80oC when the content of yttrium was 2.0wt%. In addition, 70~85% recovery of the capacity was obtained due to better antioxidation. The increase of charging/discharging efficiency with yttrium substitution for Mm in melt-spun ribbons illustrated by the potential characteristics of charging/discharging is ascribed to the flatter and lower hydride formation potential, as well as the higher hydrogen evolution potential. Moreover, This effect is more prominent with increasing yttrium content.