Abstract: Polysiloxane (PSQ) particles were introduced into the poly(lactic acid) PLA matrix by physical mixing and immobilization, and then the PLA electrospun fiber film with a bead structure was constructed. The results indicated that the introduction of PSQ was beneficial to the formation of beaded fiber, and the formation of bead structure led to a significant increase in water contact angle and porosity of PLA fiber film. In particular, the immobilization treatment of PSQ resulted in a water contact angle of 158° and a porosity of 54%, which were improved by 5% and 50%, respectively, compared to pure PLA fiber film. Moreover, the hydrophobic properties and oil flux of the fiber film were also improved significantly. The immobilization of PSQ in the PLA could inhibit its migration during the hydrolysis process. These PSQ particles could remain in the fiber film for long time to enhance the hydrophobic properties of the fiber film, leading to excellent hydrolysis resistance.