The invention discloses a light storage combined grid-connected system. The light storage combined grid-connected system comprises a photovoltaic array, a three-phase inverter main circuit, a filter circuit, a power grid, a bidirectional DC/DC converter, an acquisition module, a maximum power point tracking (MPPT) calculation module, a DC voltage/AC current double-loop control module, a bridge arm voltage modulation wave generation module, a battery current/battery voltage acquisition module, a battery DC current calculation module, a battery current closed-loop control module and a DC/DC converter modulation wave generation module which are sequentially connected. With a control method based on the system, the light storage combined grid-connected system can participate in the process of frequency modulation of the power grid like a traditional power generator set, the bidirectional DC/DC converter participates in frequency modulation to transmit or absorb power to or from the power grid when the frequency of the power grid is abnormal, the unfavorable influence of a pure photovoltaic power generation system on the power grid is reduced, and the grid-connection adaptability of a new energy grid-connected system is greatly improved.