The invention discloses a method and a system for automatic control and automatic warning. The system warns operators in various warning ways in real time and carries out prevention in advance on a progress. The invention adopts the technical scheme that the system comprises a data extracting module, an interface export module, a database module, a control limit calculation module, a specification limit setting module, a control state data analysis module, a specification state data analysis module and a command module, wherein the data extracting module is used for acquiring process data andrelated ID information; the interface export module is used for converting and exporting formats of the data and the information; the database module is used for storing the data and the information;the control limit calculation module is used for calculating a process data control limit through the acquired historical process data; the specification limit setting module is used for setting a process data specification limit; the control state data analysis module is used for comparing the process data with the corresponding control limit so as to output a control state signal depending on whether the process data exceeds the corresponding control limit or not; the specification state data analysis module is used for comparing the process data with the corresponding specification limit so as to output a specification state signal depending on the process data exceeds the corresponding specification limit or not; and the command module is used for outputting a corresponding control command to equipment and outputting a warning instruction according to the control state signal and the specification state signal. The method and the system are applied to the fields of production control and warning.