<p>Metallic glass possesses excellent properties due to its unique atomic arrangement structure, but its difficult machining characteristics sometimes make it waste unnecessary energy during machining. In this paper, the average specific cutting energy was first calculated by using the cutting force, and then the machining performance of metallic glass was studied from the perspective of the average specific cutting energy. The average specific cutting energy diminishes with power function as the feed per tooth rises. A smaller cutting thickness leads to more energy consumption and lower energy utilization efficiency. The surface roughness was positively correlated with the feed speed, and it tended to increase and then decrease with the increase of both cutting speed and milling depth. The chip edge phenomenon gradually appears as the average specific cutting energy decreases. Although reducing the average specific cutting energy can achieve higher energy utilization efficiency, it does not lead to better machined surface quality. This study provides a basis for green manufacturing of metallic glass in terms of energy utilization efficiency.</p>