The invention discloses a state-of-charge-considered centralized-control frequency modulation method of energy storage systems distributed at multiple points. The method comprises the following steps:A, the frequency (i)f(/i) of a power grid is monitored in real time; when the frequency (i)f(/i) of the power grid exceeds a frequency modulation dead zone ((i)f(/i)dn, (i)f(/i)up), the active poweradjustment amount delta (i) p(/i) is calculated according to the frequency deviation delta (i)f(/i); B, according to the respective state-of-charge (SOC) of each distributed energy storage system, grouping all distributed energy storage systems; C, when the (i)f(/i) is larger than the (i)f(/i)up, the active power command of each distributed energy storage system is calculated, and the active powercommand reference value of each distributed energy storage system is revised according to the state of charge; D, when (i)f(/i) & lt; (i)f(/di)dn, the active power command of each distributed energystorage system is calculated, and the active power command reference value of each distributed energy storage system is revised according to the state of charge. According to the invention, energy storage systems distributed at multiple points are centrally coordinated and controlled to support the frequency of the power grid. Therefore, the stability of the power grid is effectively improved.