The invention relates to a positive and negative electrode electrolyte and a preparation method thereof, and application of a positive and negative electrode electrolyte in an A11-model flow battery,belongs to the field of electrochemistry and can be widely applied to new energy large-scale energy storage. The active material of the negative electrode electrolyte in the A11-model flow battery isK3Fe(CN)6, and the constant pH of the active material of the negative electrode electrolyte is maintained by employing a hexamethylene tetramine-hydrochloric acid; the active material of the positiveelectrode electrolyte is Fe(5, 5'-dmbpy)3C12, the constant pH of the active material positive electrode electrolyte is maintained by employing a glycine-hydrochloric acid; the solid energy storage materials of the positive and negative electrodes are Prussian blue Fe4[Fe(CN)6]3; and the intermediate K3Fe(CN)6 and the Fe(5, 5'-dmbpy)3C12 are subjected to redox to achieve the transmission of electrons/charges between the positive and negative electrodes and the solid energy storage materials Fe4[Fe(CN)6]3. The energy density of the flow battery can reach more than twice of the energy density ofa current all-vanadium redox flow battery, and the cost of the active material of the flow battery is only 1/10 of that of the current all-vanadium redox flow battery.