In order to improve the properties of Co-8.8Al-9.8W-2Ta alloy, 0.4at.% Ce and B elements were added to study their effects on the microstructure and properties of the matrix alloy. The results showed that both Ce and B can inhabit the precipitation of the secondary phase, and spheroidize the secondary phase. Co₃W phase is precipitated in the grain boundary region of 0.4Ce alloy, Ce mainly formed compounds Ce₂Co₁₇ and Al₂Ce₂Co₁₅. And Co₃W and Co₇W₆ phases are mainly formed in the grain boundary region of 0.4B alloy, and B element mainly formed compound CoW₂B₂. Both Ce element and B element can improve the microhardness of the alloy, and 0.4Ce alloy owned the highest microhardness.