The invention relates to an 
imidazole onium salt anion-exchange membrane and a preparation method thereof, belonging to an anion-exchange membrane. The invention provides an 
imidazole onium salt anion-exchange membrane with better 
thermal stability and 
chemical stability and a preparation method thereof. The 
imidazole onium salt anion-exchange membrane is prepared by adopting a 
polymeric membrane, and has a 
chemical structure of one class of high polymers with side chains containing imidazole onium salt. The imidazole onium salt anion-exchange membrane has a membrane 
ionic conductivity of being more than 0.01S / cm, has better 
thermal stability and 
chemical stability and can be used at high temperature and in a strong acid, strong alkali and strong 
oxidizing agent. The preparation method comprises the steps of: soaking a 
polymeric membrane in 
acetone, and 
drying to constant weight after cleaning; radiating a film by high-energy rays; placing the radiated film in a container, injecting monomers in the container to ensure that the film is completely immersed into the monomers, vacuumizing, charging 
inert gases to the container until no air exists in the container, placing a water bathfor reacting after sealing, removing unreacted monomers, and 
drying; and soaking the grafted film with a quaternization 
reagent, and washing with deionized water to obtain the imidazole onium salt anion-exchange membrane.