The invention discloses a method for preparing solid-phase microextraction fibers with a polyion liquid bonding coating on a metal wire carrier, particularly relates to a preparation method by utilizing a surface-initiated atom transfer radical polymerization reaction to graft an ionic liquid on the metal wire in a situ polymerizing manner. The novel method is characterized in that the method comprises the steps of adopting the metal wire as the carrier, performing chemical silvering on the surface of the metal wire firstly, then performing hydroxylation on the silvered layer, bonding an atom transfer radical polymerization initiation site, and preparing the polyion liquid bonding coating on the surface of the metal wire with the ionic liquid containing alkenyl as a monomer by utilizing the surface-initiated atom transfer radical polymerization technology. The solid-phase microextraction fibers prepared by the preparation method disclosed by the invention have the advantages of high mechanical strength, good coating stability, good extraction property and the like, can be used for enrichment analysis of trace components of samples of food, environment, drugs and biochemistry and the like, and are very good in application potential.