A data interface metal housing, machining method thereof and machining device, the machining method comprising the following steps: providing a metal flat tube (200); sleeving the metal flat tube (200) on a mold core (111), the mold core (111) being provided with, in an axial direction thereof, at least two mold core sections (114, 115, 116, 117) having different sectional dimensions; and utilizing at least two cavities (1221, 1222, 1223, 1224, 1225) to cooperate with the mold core (111) to extrude the metal flat tube (200), such that the metal flat tube (200) is extruded along the axial direction of the mold core (111) into metal tube sections (301, 302, 303, 304) respectively corresponding to each mold core section (114, 115, 116, 117). The method extrudes a metal tube by steps, thus manufacturing a complex irregularly-shaped metal tube having a poor stretchability into the metal housing having different shapes, and preventing a metal tube fracture.