Abstract: Two methods are proposed to quantitatively evaluate the product machinability under the fact that the manufacturing resources of an actual manufacturer are limited.In the first method,the product machinability is synthesized through evaluating its each feature by the fuzzy machinability functions defined for each equipment.In the second method,the product machinability is evaluated directly with the fuzzy machinability functions established for each typical processing feature.Three synthetic approaches are presented for the synthesis of single machinability criterion.The merits and shortcomings of each evaluation method and each synthetic approach are discussed,and the preferred criteria are given.