Abstract: The paper proposed a design scheme of antenna structure of underground intrinsic safety wireless pressure sensor, and researched impact of opening parameters of metal shell and antenna position on antenna gain. The simulation and test results show that antenna gain increases with increase of length and width of metal shell opening, but increased amplitude gradually decreases; antenna gain increases with decrease of distance between antenna and opening; antenna gain increases about 2 dB when metal shell thickness of opening side reduces 1 mm; antenna gain changing caused by millimeter level changing of metal shell space height almost can be ignored; antenna gain achieves the best and antenna transmission distance is about 14 m when metal shell with length and width of opening are 1/4 and 1/8 of antenna wavelength respectively, thickness is 2 mm, space height is 41 mm, and distance between antenna and opening is 1.4 mm.