The invention relates to the technical field of solar groove type solar thermal electric power generation, in particular to a heat tank control device, combined with weather prediction data, of a groove type solar thermal electric power generation system. The heat tank control device comprises a numerical weather prediction receiver, a heat tank flow adjustment control unit and a central coordination control unit. The numerical weather prediction receiver receives numerical prediction data through the network. Numerical calculation is carried out through the numerical prediction data to solve a hydromechanical and thermodynamic equation set for describing the weather evolution process, and short-term solar resource prediction data are obtained. By means of the heat tank control device, combined with the weather prediction data, of the groove type solar thermal electric power generation system, the mass of hot melting salt stored in the system within a period in the future is estimated through numerical weather prediction, and flow control is carried out on a heat tank melting salt outlet pump according to the mass of the hot melting salt stored in a heat tank and the power grid dispatching power output requirement.