A system for generating milling codes includes a plurality of personal computers (10), a database (14), and an application server (12). The application server, connected between the personal computers and the database, includes a circular hole handling module (125), for handling circular holes of an engineering drawing, and receiving relevant parameters of the circular holes; a non-circular hole handling module (126), for determining and handling all non-circular holes of the engineering drawing, and receiving relevant parameters of the non-circular holes; a milling path generating module (128), for generating milling paths according to the parameters of the circular holes and the non-circular holes; and a milling code generating module (129), for generating milling codes according to the milling paths. A related method for generating milling codes is also provided.