The challenge system in the criminal procedure law is to ensure the fairness of the trial and strictly limit the identity of the participants in the case. Judges, prosecutors and case investigators are parties or close relatives of the case, and if they have participated in the case and have an interest in it, they should withdraw.
Legal objectivity:
Article 30 of the Criminal Procedure Law of People's Republic of China (PRC) * * * Judges, prosecutors and investigators shall not accept guests and gifts from the parties and their clients, and shall not meet the parties and their clients in violation of regulations. Judges, prosecutors and investigators who violate the provisions of the preceding paragraph shall be investigated for legal responsibility according to law. The parties and their legal representatives have the right to ask them to withdraw.