Co64V15Si21 − xGax alloys undergo L21/D022 martensitic transformation. Martensitic transformation temperatures of Co64V15Si21 − xGax alloys are reduced by the increase of Ga content. Co64V15Si17Ga4 alloy shows excellent high-temperature thermal cycle stability. Shape memory effect of Co64V15Si21 − xGax alloys is enhanced by Ga increasing.