▎ 摘　　要

NOVELTY - Method for preparing multi-element doped graphene fiber, involves (i) injecting graphene oxide solution into coagulation bath using wet spinning method, gelatinizing, precipitating graphene oxide to obtain graphene oxide fibers, where the coagulation bath is aqueous solution of ionic liquid, (ii) performing reduction treatment on graphene oxide fibers obtained in step (i) to reduce oxygen-containing functional groups on the surface of the graphene oxide, and drying the graphene fibers to obtain graphene fibers, and (iii) calcining the graphene fiber obtained in step (ii) in inert atmosphere, carbonizing the graphene fiber to obtain the product, where the ionic liquid comprises nitrogen, boron, phosphorus, sulfur and/or fluorine. USE - Method for preparing multi-element doped graphene fiber used as electrochemical biosensor (all claimed), microelectrode in electrochemical sensing system and detecting biological small molecules. ADVANTAGE - The method has excellent conductivity and high electrochemical activity, is simple to process, environmentally-friendly and economical, and easily detect the defects.