Through the evolution of hundreds of millions of years,the living creature have superior structure and function such as the structure of non-smooth surfaces have a well water-repellent,drag reduction,adhesion reduction functions.This study chose a kind of widely used material gray cast iron as substrate,which the metal and nano-ceramic nanocomposite coatings by electrodepositon on gray cast iron surface were prepared.The 2-D and 3-D surface morphologies of composite coating were observed and the result indicated that 2-D and 3-D had a typical geometrical non-smooth character.Furthermore,the contact angles of coating were measured.The relation between coating morphology and wettability was analysed.Therefore,the water-repellent of the composite coating surface was due to the characteristic microstructure and content of coating. Through the evolution of hundreds of millions of years, the living creature have superior structure and function such as the the structure of non-smooth surfaces have a well water-repellent, drag reduction, adhesion reduction functions. gray cast iron as substrate, which the metal and nano-ceramic nanocomposite coatings by electrodepositon on gray cast iron surface were prepared. 2-D and 3-D surface morphologies of composite coating were observed and the result indicates that 2-D and 3 -D had a typical geometrical non-smooth character .Furthermore, the contact angles of coating were measured. The relation between coating morphology and wettability was analyzed. Herefore, the water-repellent of the composite coating surface was due to the characteristic microstructure and content of coating.