Material machinability evaluation is the basis of a reasonable manufacturing process. Material machinability can be evaluated qualitatively and quantitatively using the radar-graph method. However, two key questions remain unresolved, and these are indicator weight confirmation and effective evaluation. A comprehensive evaluation method is proposed to address the first question. A statistical method is used to compute the indicator weight, which is determined by a subjective or objective weighting method. An optimization model is established based on minimizing the total deviation between the original evaluation weight and the combination weight. As to the second question, a comprehensive evaluation index K, including the area vector and perimeter vector of a radar-graph, is defined to quantitatively evaluate material machinability. Machinability examples of Ti6Al4V titanium alloy, AISI316L stainless steel, P20 mold steel, 20 steel, and normalized 45 steel are provided. The results show that the method is feasible, reliable, and effective.