Primary air fan tripping set run back control method and system

The invention discloses a primary air fan tripping set run back control method and system. The method includes that : when the primary fan is tripping, a set run back instruction is sent out to control the set to run back; primary air system pressure and coal mill blowing rate are monitored, a coal mill stopping signal is sent out when determining that the primary air pressure and the coal mill blowing rate can not maintain the operation of the coal mill; and the set is controlled to run back again by sending out a coal mill tripping instruction and a secondary set run back instruction according to the coal mill stopping signal. By adopting the invention, the success rate of the primary air fan tripping set run back can be improved.