The invention discloses a foam drainage gas recovery chemical reagent filling device, and belongs to the field of oil and gas recovery equipment. The chemical reagent filling device comprises a base,a chemical reagent preparation assembly, a chemical reagent filling assembly and an electrical control assembly, the chemical reagent preparation assembly comprises a chemical reagent supplement pump,a stirring tank and a water replenishing valve, an outlet of the chemical reagent supplement pump communicates with the stirring tank, a stirrer and a liquid gauge are arranged in the stirring tank,the chemical reagent filling assembly comprises a filling pump set and a chemical reagent filling pipe network, the filling pump set and the chemical reagent filling pipe network are connected, the electrical control assembly is electrically connected with the chemical reagent supplement pump, the water replenishing valve, the filling pump set, a switch valve and the stirrer separately, the controller can control the switch valve, at the outlet end, communicating with a well or a gas-liquid separator which needs to be filled, and thus a chemical reagent in the stirring tank is injected into the well or the gas-liquid separator. Preparation and filling of the chemical reagent are controlled through the controller, meanwhile, different outlet ends are conveniently controlled for filling, control is convenient, the automation degree is high, and the production efficiency is advantageously improved.