The contents of IgG Fc receptor of 141 Group A Streptococcal isolates were detected with immunoblot,an assay based on the binding of enzyme labelled immunoglobulins G. The results showed:IgG Fc receptor could be found among 98% of all isolates. The contents of IgG Fc receptor had no difference among different M/OF strains or strians from different kinds of diseases. This method offered several advatages over previous ones:High sensitivity,good repetition,allowing tests to be performed quickly and easily,result being determined visually. It indicated that this method was better than other ones in detecting IgG Fc receptor of Group A Streptococci. It is necessary to study more on the relationship of the contents of IgG Fc receptor among different kinds of diseases and M/OF types.