The treatment of oily wastewater through electrospun membrane is a promising method due to the resulting membrane with high porosity and interconnected pore structure that could lead to high permeation performance. Conventional electrospun membranes such as polyacrylonitrile (PAN) and poly(vinylidene fluoride)(PVDF) have been reported to effectively purify oily wastewater. However, the disposal process is inevitable due to membrane fouling, posing a severe threat to the environment. In this work, we propose a membrane composed of biodegradable materials to overcome this problem. Polycaprolactone (PCL)-based membrane is biodegradable, biocompatible, and durable. Moreover, subsequent grafting with carboxymethyl cellulose (CMC) not only enhances the hydrophilicity of the membrane but also induces electrostatic repulsion against the oil-in-water emulsion stabilized by the negatively charged surfactants, weakening the adhesion of the emulsion droplets to facilitate the regeneration process.