The utility model discloses a plane-type coal gas filling device applicable to model test. The plane-type coal gas filling device comprises an aerating panel, wherein one end of the aerating panel is connected with an aerating pipe; an aerating switch is arranged on the aerating pipe; the aerating panel comprises a panel on which crisscross communicated gas guiding grooves are arranged; the gas guiding grooves are communicated with the aerating pipe through an aerating channel on the terminal of the panel; a lower layer sieve plate, a steel wire mesh and an upper layer sieve plate are arranged on the panel in turns; edge joints of the lower layer sieve plate, the steel wire mesh, the upper layer sieve plate and the panel are sealed by rubber sealing strips; fixed pressing strips are arranged on edges of the layer sieve plates; and the lower layer sieve plate, the steel wire mesh and the upper layer sieve plate are fixed on the panel by bolts. The plane-type coal gas filling device provided by the utility model is capable of uniformly and quickly filling gas into a tested coal layer on a large area, has good gas permeability and boundary binding force, is capable of filtering fine coal powder, incapable of breaking a model and leaking the gas on lateral sides and capable of regulating the flow rate and the pressure, and is high in safety, simple in structure, perfect in performance, low in cost and convenient to maintain and replace.