The invention discloses a gas field testing device and aims at solving the problem of gas field testing in a rigid container which is sealed by a screw plug. The gas field testing device disclosed by the invention comprises a sampling bin, a sealing tape, gas guide pipes, a screw rod, a pressure gauge, a flowmeter and the like, wherein the tail end of the container is entirely wrapped by the sampling bin, sealing sludge is filled in the sampling bin, and the sampling bin is fixed by the sealing tape; the screw rod is pre-placed in the sampling bin and three gas guide pipes are introduced, wherein a gas extraction guide pipe is connected with the pressure gauge and a vacuum pump, a gas inlet guide pipe is connected with argon gas through the flowmeter, and a test guide pipe is connected with a gas testing instrument; before testing, volume calibration is performed by vacuum pumping and argon gas filling; and the screw plug is opened by the screw rod, gas enters the sampling bin and the testing is completed by the gas testing instrument. The gas field testing device disclosed by the invention is applicable to field testing of the gas in the rigid container which is sealed by the screw plug.