The embodiment of the invention discloses an energy storage system output delay compensation control method and a device. The method comprises steps: according to a set sampling frequency, operation state information of a generator set and a power grid AGC (Automatic Generation Control) instruction are acquired periodically; according to the operation state information, an expected output value of the generator set after the energy storage system delays for a length of time is predicted; on the basis of the expected output value and the power grid AGC instruction acquired at the current sampling time, an energy storage system output instruction of the energy storage system is determined, and the energy storage system is controlled to respond to the energy storage system output instruction. Thus, by using the scheme of the invention, during the process during which the energy storage system and the generator set coordinate to respond to the power grid AGC instruction, the energy storage system output delay is compensated, combined output of the generator set and the energy storage system can be more precisely controlled, and effects of a response to the power grid AGC instruction are enhanced.