Alloy cast iron cylinder is the mainstream product used in engine nowadays. However, the machinability of alloy cast iron is poor because of its enhanced mechanical properties. In this paper, turning experiment has been conducted to study machinability of alloy cast iron with uncoated and coated carbide tools under dry cutting condition. The results of the experiment indicated that the turning performance of alloy cast iron with coated tool was much better than uncoated tool in terms of cutting force coefficients and tool wear. Feed rate has a great influence on surface roughness, and appropriate tool wear is benefit of finished surface roughness.