According to the way and correction method of criminal trial supervision

The way of criminal trial supervision: appearing in court; Out-of-court investigation; Attend the judicial Committee as a non-voting member; Review judgments and rulings. Correction methods: oral supervision, criminal protest to investigate the responsibility of offenders, notice of correction of violations and procuratorial opinions.

legal ground

Article 254 of the Criminal Procedure Law

If the presidents of the people's courts at all levels find errors in ascertaining facts or applying laws in legally effective judgments and rulings, they must submit them to the judicial committee for handling. The Supreme People's Court has the right to send back or instruct the people's courts at lower levels to retry the legally effective judgments and rulings of the people's courts at all levels. If the people's courts at higher levels find that there are indeed mistakes, they have the right to send back or instruct the people's courts at lower levels to retry. The Supreme People's Procuratorate has the right to lodge a protest with the people's court at the same level in accordance with the procedure of trial supervision if it finds that the legally effective judgment or ruling of the people's court at all levels is wrong, and the people's procuratorate at a higher level has the right to lodge a protest with the people's court at the same level in accordance with the procedure of trial supervision. When a people's procuratorate protests a case, the people's court that accepts the protest shall form a collegiate bench for retrial. If the facts of the original judgment are unclear or the evidence is insufficient, the people's court at a lower level may be ordered to retry.