The invention provides method and device for processing wind power monitoring system data. The method comprises the following steps of: acquiring wind power system data to be monitored and storing the wind power system data to be monitored into a buffer register layer; storing the data to be monitored into a short-term memory layer and judging whether the data to be monitored in the short-term memory layer periodically fluctuates around a preset normal value when judging whether the offset preset normal value of the data to be monitored in the buffer register layer is greater than a preset fault threshold; if yes, storing the data to be monitored into a preset storage area, and if not, storing the data to be monitored into a long-term memory and alarm layer and carrying out the fault diagnosis and processing on the data to be monitored in the long-term memory and alarm layer; and otherwise, forgetting the data to be monitored. By processing the data to be monitored in three levels according to the memory mode angle, the processing on the data to be monitored can be selectively finished, the pressure for storage and subsequent fault processing can be greatly reduced ,which has important value for optimal design of monitoring systems of large-sized large-scale wind power systems.