Polypyrron with sulfated side chain and preparation method of polypyrron

The invention provides a polypyrron with a sulfated side chain. The content of sulfonic acid groups in the polypyrron can be controlled; and such polypyrron with the sulfated side chain can be used for preparing a proton exchange membrane which is high in conductivity, excellent in mechanical performance and low in cost. The invention also provides a preparation method of the polypyrron with the sulfated side chain, and also provides the proton exchange membrane.