Dopamine (DA) is utilized to form polydopamine (PDA) through polymer deposition on the surface of octadecylamine (ODA) to construct water-based ODA@PDA nanoparticles, and then ODA@PDA nanoparticles are used as a finishing agent to prepare superhydrophobic silk fabric. The optimized preparation condition of ODA@PDA is 2 g/L DA, 1.0% ODA, aggregation sedimentation time of 24 h. Transmission electron microscopy (TEM) and particle size distribution analysis indicate that the ODA@PDA nanoparticles produced by the optimized process exhibit uniform spherical morphology with an average particle size of approximately 300 nm. Fourier-transform infrared spectroscopy (FTIR) analysis confirms that PDA and ODA are successfully introduced on the surface of the modified silk fabrics, imparting them with superhydrophobic properties. The ODA@PDA modified superhydrophobic silk fabric maintains static contact angle above 145° after 10 cycles of O₂ plasma etching and photothermal repairing, demonstrating excellent self-repairing capabilities. Furthermore, the modified fabric also shows good self-cleaning ability, chemical stability and washability.