Abstract: The synergistic effects of the metal surface treatments and interleaves on the interlaminar mechanical properties of the carbon fiber reinforced plastics (CFRP) composite-thermoformed steel super-hybrid laminates were investigated. Double cantilever beam tests (DCB) show that the Mode-I interlaminar fracture toughness of the laminates can be greatly improved by combining metal surface treatment and inserting interleaf. Among them, the interlaminar Mode-I fracture toughness of the specimens with sandblasting/adhesive film interleaves (GB36#/AF) and sandblasting/epoxy resin interleaves (GB36#/EP) increase by 343% and 129% compared with that of the degreased specimens respectively. In addition, based on the cohesive zone model, the delamination of the CFRP-thermoformed steel super-hybrid laminates was analyzed by finite element method. Finally, to uncover the toughing mechanism, confocal laser scanning microscopy (LSM), contact angle goniometer (CAG) and scanning electron microscopy (SEM) were employed to characterize the surface morphology of the thermoformed steel and the fracture surface of the tested laminates.