In this study, the nanoparticles of metal-organic framework ZIF-8 are incorporated into the poly(lactic acid) (PLA) to prepare the nanocomposite electrospun membrane. The diameter and the surface roughness of the fibers can be successfully controlled by increasing the content of ZIF-8 in the membranes. The prepared PLA/ZIF-8 membranes have increased oil wettability and significantly improved mechanical property compared with pure PLA membrane. The tensile strength, stain at break of PLA/ZIF-8 membrane with 0.5 wt% ZIF-8 are increased to 5.02 MPa and 88.81% compared to 2.77 MPa and 57.89% for pure PLA membranes, respectively. The PLA/ZIF-8 membranes are proved to be good candidate for oil/water separation with high efficiency because of the fast oil wetting ability, the roughness of fibers, and the adsorption effect of the porous ZIF-8 nanoparticles.