The utility model belongs to the technical field of construction site corollary equipment. The air and water pipe machining support for the subway comprises a base. The problem that a subway air-waterpipe machining and spraying auxiliary device is not suitable for air-water pipes of all specifications is solved. The support comprises two independent support units which are symmetrically arrangedand used in cooperation. Each independent support unit comprises a horizontally-arranged base, two symmetrically-arranged supporting rods are vertically fixed to the upper portion of each base, horizontally-arranged fixing shafts are connected to the tops of the supporting rods respectively, bearings are connected to the fixing shafts, the fixing shafts are fixed to inner rings of the bearings, and a to-be-machined air-water pipe can be placed between outer rings of every two adjacent bearings. By means of the two independent support units, air and water pipe fittings with different lengths and various pipe diameters can be machined without dead corners, operators can sit and stand for construction, and physical discomfort caused by long-time half squatting and stooping is effectively avoided.