The invention relates to an experiment device and a method for measuring the interlayer fluid channeling quantity of a multilayer commingled production gas well. The device comprises a stratum simulator, wherein multilayer rock cores are arranged inside the stratum simulator in a laminated way; a gas-permeable separation layer is arranged between the adjacent rock layers; deformable sealing pads are arranged between the top wall of the stratum similar and the corresponding rock core and the bottom wall of the stratum simulator and the corresponding rock core, so that a burden pressure fluid chamber is formed between the top wall and/or the bottom wall and the corresponding sealing pad; a plurality of measuring gas inlets communicated with the corresponding rock core are formed in the side wall of a casing of the stratum simulator; a burden fluid inlet communicated with the burden pressure fluid chamber is arranged on the bottom wall of the casing of the stratum simulator; simulation oil pipes extend to pass through the top wall of the stratum simulator; lower end openings of the simulation oil pipes extend into the rock cores to be measured; the simulation oil pipes are used for introducing out measuring gas; and the difference value of the air inlet quantity and the air outlet quantity of the rock cores to be measured is the interlayer fluid channeling quantity.