Abstract: SnCo0.9Y0.1 alloy was synthesized using solid-state sintering and ball milling, and effects of milling time and carbon addition on the microstructure and electrical properties were analyzed. The results show that the SnCo0.9Y0.1 alloy was mainly composed of CoSn and CoSn2, the phases did not change after milled, but the grain size decreased first and then tended to be stable with the prolongation of milling time. After adding carbon, phases of the alloy did not change, carbon and the alloy phase formed physical mixture. Initial discharge capacity and initial charge-discharge efficiency of the SnCo0.9Y0.1 alloy were 300 mA·h·g-1 and 73.0%, it remained above 75.0% of the initial discharge capacity after 25 charge-discharge cycles. After milled, charge-discharge capacity and cycle performance increased first slowly and then tended to be stable, but initial charge-discharge efficiency decreased gradually as the milling time increased. Adding carbon made cycle performance of SnCo0.9Y0.1 alloy better, and it remained above 85.9% of the initial discharge capacity after 25 charge-discharge cycles.