Jury trial is both a judicial approach to case-fact and a political form of extending citizens' rights in countries of common law tradition. By sorting out of historical events and analyzing the current situations,the author,from a perspective of institutional function,points out that the jury trial in Irish criminal procedure generally cannot meet the country's needs in terms of justice and politics,which is determined by Ireland's special circumstances. To attain its healthy development and effective administration,any institution must agree with the political,economic,cultural and legal situations of the country where it intends to take root.