In order to obtain polyclonal antibodies against the fibrillar(Fiber)protein of fowl ade-novirus serotype 11(FAdV-11)and investigate its cross-reactivity to different serotypes of FAdV Fiber,the gene encoding the FAdV-11 Fiber protein was cloned into a prokaryotic expression vec-tor pET-32a by homologous recombination technology,then the plasmid was transformed into BL21(DE3)receptor cells,and the purified recombinant protein was used as an immunogen to im-munize rabbits to prepare polyclonal antibody after induced expression,and the cross-reactivity of the polyclonal antibody against different serotypes of FAdV Fiber proteins was identified by West-ern blot and indirect immunofluorescence(IFA).The results showed that the His-FAdV-11-Fiber recombinant protein was mainly expressed as inclusion bodies and was well expressed.Western blot and IFA showed that the prepared polyclonal antibody reacted with the Fiber proteins of FAdV-8a,FAdV-8b,and FAdV-11,but did not with the 2 Fiber of FAdV-4(Fiber 1 and Fiber 2)proteins.In conclusion,in this study,we successfully prepared rabbit polyclonal antibodies against FAdV-11 Fiber and showed that it specifically recognized the Fiber proteins of FAdV-8a,FAdV-8b and FAdV-11,which lays the foundation for further establishment of serological differential diag-nosis of FAdV-11.