The invention relates to a method for a battery energy storage response frequency modulation signal in defined states of charge, and relates to the technical field of battery energy storage frequencymodulation power generation. The method includes the following steps: obtaining the states of charge defined at the beginning and the end of a time period and the battery energy storage frequency modulation basic information; and establishing, by using a dynamic programming method, a mathematical model of the charging-discharging power of the battery energy storage response frequency modulation signal, and working out the optimal solution of the charging-discharging power of the battery energy storage tracking frequency modulation signal by using an objective function to maximize the battery energy storage tracking accuracy. The method is helpful to improve the system frequency stability.