A superhydrophobic, superoleophilic, and environmentally friendly composite membrane of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] and deacetylated cellulose acetate (SiO2@PHBH/dCA) was developed using electrospinning and surface silanization modification techniques. In this investigation, a simple strategy was proposed to prepare biodegradable PHBH/CA composite nanofiber membranes via electrospinning, followed by short-term alkali treatment to enhance the surface activity of the nanofibers. The sol-gel impregnation method of methyltrimethoxysilane (MTMS) and tetraethyl orthosilicate (TEOS) was used to in situ grow low surface energy silica particles on the surface of nanofibers. It demonstrated self-cleaning and anti-fouling capabilities against dust and dirty water droplets and maintained hydrophobicity even after soaking in strong acid and alkali solutions for 12 h, demonstrating its excellent durability. Furthermore, the oil-water separation efficiency for test liquids such as hexane, kerosene, and sunflower oil exceeded 98.29 %, indicating promising potential for oil-water separation. After 56 days of soil composting, the biodegradation rate of the SiO2@PHBH/dCA composite nanofiber membrane reached 73.68 %, showing good biodegradation performance. Therefore, this innovative work provides valuable insights into the silanization modification of single nanofibers and holds broad prospects in the field of hydrophobic and biodegradable membrane materials.