The invention discloses a composite energy absorption tube machining device which comprises a rectifier (1), a resistor (2), a switch (3), a capacitor (4), a boosting transformer (5), an upper fixing plate (6), a fixing bolt (7), a pressing block (8), a mould frame (9), a constraint mould (11), a coil (12), a lower fixing plate (13), a T-shaped platform (14), an exhaust vent (16), a fixing groove (17) and a wire hole (18). Compared with a hydraulic forming method and a mechanical bulging method, a composite metal energy absorption forming method based on the electromagnetic forming principle and used in the composite energy absorption tube machining device is high in machining efficiency and high in the pipe fitting forming speed and enables composite metal tubes to be formed under the high strain rate; due to the fact that the high strain deformation process can be used for forming metal materials which are deformed difficultly through a conventional method, the plasticity of the metal materials is greatly improved, and the yield strength of the materials is greatly improved. Different wave forms and reinforcing ribs can be formed by changing the shape of the constraint mould in a mould body, and the machining flexibility is high.