Abstract: Polarization behaviour of electroless amorphous Ni-P alloy coatings have been investigated in 1mol/1 NaOH solution using potentiodynamic method, and surface films at different potentials have been analysed on the basis of XPS method. Results indicate:the anodic dissolution current does not decrease with the increase of P content in the Ni-P alloy, even though there exists H₂PO₂^- and PO₄^- on the surface film, anodic dissolution of alloys has not been inhibited effectively. The intense hydrolization of P may be the cause of making the dissolution current of Ni-P alloy higher than that of Ni.