In the paper, the microstructure of PS45 coatings prepared by high velocity electric wire arc spraying was investigated by scanning electron microscope. Bonding strength was tested by electron tensile testing machine. The interface morphology of PS45 coatings was acquired by means of picture analysis and processing technology, the computing programs of fractal dimensions and multifractal spectrum were designed in Matlab language. The relations of the bonding strength to spray voltage and fractal dimension and multifractal spectrum were discussed. The results of analysis and calculation show that the better the bonding strength of PS45 coatings is, the more complicated the interface morphology and bigger fractal dimensions are. With spray voltage gone up, the better the interface uniformity is, the smaller the spectrum width is.