The invention belongs to the technical field of electric power system operation control, and particularly relates to a non-delay optimal reactive power coordinated control system and method for a multisource-containing power grid. The method comprises the following steps: obtaining meteorological factors and power grid flow information at historical moments of the multisource-containing power grid; predicting to obtain reactive power of an optimal wind field grid-connected node/a photovoltaic power station grid-connected node/an SVG grid-connected node/a thermal power grid-connected node/loading in the future; increasing the power grid inductive reactive power when the current power grid is under surplus capacitive reactive power; increasing the capacitive reactive power of the power grid when the current power grid is under insufficient capacitive reactive power. Multisource-power grid reactive power coordinated control terminal devices are respectively connected between a wind power generation system and the power grid, between a photovoltaic power generation system and the power grid, between a thermal power generation system and the power grid, between a load A and the power grid as well as between the power grid and a load B. According to the invention, the phenomenon that all the regulation results of a power grid reactive power flow adjusting method are obtained after the network state at the flow information acquisition moment is avoided, and the control information can correspond to the acquisition information without time difference.