Abstract: Atomic layer deposition (ALD) technology is a surface self-limiting thin film growth technology that can control the coating thickness precisely.We studied ALD coated polyolefin film to form nano-alumina polyolefin composites.However, the non-reactive groups on the polyolefin film cannot initiate ALD growth directly, resulting in a low growth efficiency in the early stage reaction and final formation of alumina clusters on polyolefin surface.To improve the properties of polyethylene (PE) membrane coated by ALD alumina, the PE membrane surface was modified with polyvinyl alcohol (PVA) and then followed up with ALD Al₂O₃.The effects of PVA modification on ALD alumina coating PE film were characterized by means of scanning electron microscopy, Fourier Transform infrared spectroscope and Inductive coupling plasma emission spectrometry.The results indicated that the PVA surface modification could increase the hydroxyl group (-OH) on the PE film as the ALD reaction sites effectively.When the PE film surface was modified with PVA, the subsequent ALD growth efficiency was improved significantly, and alumina thin film formation on PE membrane fibers instead of island-shaped Al₂O₃ cluster was achieved.It was also found that the thermal shrinkage of the modified composite film was enhanced, thickness increase of the composite film and the damage of the mechanical structure were reduced as well.