The invention belongs to the field of electrochemical energy storage and particularly relates to a group balanced control device and method for an energy-storage liquid metal battery. The group balanced control device for the energy-storage liquid metal battery comprises N serially connected liquid metal battery units, a voltage detection module, a balanced control module and a balanced circuit module; multiple liquid metal battery monomers with higher consistency are screened and are firstly connected in series and later connected in parallel to form one battery unit, and the battery units are placed in the same high-temperature incubator. The invention further discloses a group charge and discharge balanced control method of the energy-storage liquid metal battery. By means of the control device and the control method, the defect that initiative balanced control is difficult to implement due to the fact that a voltage platform of the liquid metal battery is low and wide can be overcome, the control method and the control device can meet the requirement for the high-temperature environment during group use of the liquid metal battery, and the complexity of the balanced control device and control method is reduced, so that the energy storage use demands of the liquid metal battery are met.