Legal aid refers to a legal guarantee system that legal aid agencies set up by the government organize legal aid lawyers to provide free legal services for people with financial difficulties or special cases. Special case means that according to Article 34 of the Criminal Procedure Law of People's Republic of China (PRC), the defendant in a criminal case is blind, deaf or dumb, or the minor has not entrusted a defender, or the defendant may be sentenced to death without entrusting a defender, and should receive legal aid.