The utility model relates to the technical field of a pressure gage assembly and specifically relates to a universal joint of a pressure gage. The universal joint of the pressure gage comprises a movable nut, a T-shaped joint and a pressure gage, wherein a lower end of an internal hole of the movable nut is fixed with a spacing ring bench, a diameter of the spacing ring bench is smaller than that of an upper end of the T-shaped joint, the upper end of the T-shaped joint is located on the spacing ring bench, the joint of the pressure gage and the internal hole of the movable nut are fixedly connected through threads and press tightly against at the upper end of the T-shaped joint, a lower portion of the T-shaped joint is fixed with a lower joint, and an internal portion of the T-shaped joint has a through-hole. The universal joint of the pressure gage has a reasonable and compact structure, is convenient to use, can adjust a disc direction of the pressure gage at will, realizes firm connection, has excellent sealing performance and can be applicable to replacement connection of various specifications.