Abstract: It is difficult to collect data and evaluate the status of NC machine tools automatically because of the diversity of isomeric CNC systems. Aiming at this problem, a general method is designed. First, an energy consumption data collector is designed to collect energy consumption data of NC machine tools' spindle and the data feature is analyzed. Then the standard energy consumption data by NC machining simulation or pre-acquisition during the operation of every NC code program is collected and further a standard energy consumption database is built according to the standard data. Second, to judge the type of work piece and the status of NC machine tools, the time series theory is used to deal with the energy consumption data by compared with the data that of the standard database. Finally, the feasibility and reliability of the proposed method is verified through an example.