To reduce the environmental pollution and meet the needs for wearable electronic devices， new requirements for electromagnetic interference (EMI) shielding materials include flexibility， biodegradability， and biocompatibility. Herein， we reported a polypyrrole (PPy)- coated zein/epoxy (ZE) ultrafine fiber mat which was inherently biodegradable and skin-friendly. In addition， its ultrafine fibrous structure could be kept after coating and provided the mat with mechanical compliance， high porosity， and a large specific area for high EMI shielding. With the assistance of the epoxide cross-linking， the breaking stress of the PPy/ZE fiber mats could achieve 3.3 MPa and 1.4 MPa and the elongations at break were 40.1% and 83.0% in dry and wet states， respectively， which met the needs of various wearable electronic devices. Along with the extension in the PPy treatment duration， more PPy was loaded on the fiber surfaces， which formed more integrated and conductive paths to generate increasing conductivities up to 401.76 S·m~(-1). Moreover， the EMI shielding performance was raised up to 26.84 dB. The biobased mats provide a green and efficient choice for EMI shielding materials， which may be a promising strategy to address EMI problems in multiple fields.