Abstract: The surface of 304 stainless steels was first disposed by polishing, etching and annealing to achieve micronano structures, and then the PA6/stainless steel samples were fabricated by a hotpressing molding method without using any adhesives.The mechanical characterization results indicated that the joint strength of the resulting samples was only 3.31 MPa after polishing.However, the joint strength of PA6/stainless steel samples reached 17.48 MPa after successively polishing, etching and annealing.There is a transition in failure mode observed from adhesive to cohesive.The surface morphologies of the samples were investigated by scanning electron microscopy and atomic force microscopy, and some micronano holes were observed on the surface of stainless steel after etching.It was deduced that the plastic melt could permeate into the micro and/or nano holes on the surface of stainless steel to generate an anchoring effect during the hotpressing molding process.Fouriertransmission infrared spectroscopic result indicated that PA6 was chemically bonded with the oxides on the annealed metal surface.Such anchoring and chemical bonding effects could improve the mechanical properties of PA6/stainless steel samples.