The invention discloses an alarm optimization design method for a main control system of a wind turbine generator. Multi-dimensional state codes are used to realize a grading alarm function of a unitequipment operation state. The multi-dimensional state codes are divided into event state codes and accident state codes, have automatic triggering and automatic resetting functions, perform logic criterion operation according to input parameters and initialization parameters to determine automatic activation and resetting of the state codes, and provide the state codes for other functional modesof the master control system. After the state code event meeting the set level condition is activated, a fault recording method based on annular buffer area sliding window rolling updating is adoptedto automatically capture values of operation parameters within the target time section width before and after an accident occurs, and the values are stored as files for unit accident recalling. According to the method, multi-dimensional state code attributes are fully considered, safe operation of the wind turbine generator under the unattended condition is achieved, and the method is stable, reliable and easy to achieve and deploy.