Objective In order to investigate the influence of the modified surface on microbial fouling, the microbial fouling experiment of slime-forming bacteria on the composite coating of Ni-P-PTFE was conducted in this study. Methods Several composite coatings with different properties were prepared by electroless plating on the surface of carbon steel and the parameters such as plating thickness, plating speed and surface energy were obtained. The microstructure of electroless composite plating of Ni-P-PTFE and low carbon was compared by scanning electron microscopy, and the slime-forming bacteria microbial fouling experiments of low carbon steel and the composite coatings samples were conducted. The variation of bacteria amount in the bacterial suspension and weight variation of the samples were documented; The macroscopic and microscopic morphologies of the composite coatings were obtained and analyzed before and after the slime-forming bacteria fouling experiment, with low carbon steel as a control, the relationship between surface energy of the composite coatings and fouling deposit on the coatings was discussed. Results The surface properties of heat exchanger were changed by Ni-P-PTFE coating, as the contact angle increased significantly, and the surface energy of the samples decreased from 49. 16 mJ / m2(carbon steel) to 7. 54 mJ / m2( composite coating steel). The number of slimeforming bacteria in the suspension containing the composite coatings reduced markedly, and the average volume of dirt deposited on the coatings reduced from 12. 1 g / m2(carbon steel) to 2. 3 g / m2(composite coating steel). Conclusion It is reasonable to believe that the Ni-P-PTFE coating on low carbon steel could effectively inhibit the growth of mucus-forming bacteria, and the lower surface energy brought by the coating could reduce the deposition of microbial fouling. The composite coating showed excellent corrosion resistance and anti-fouling performance.