legal ground
Article 286 of the Criminal Procedure Law If a person was under the age of 18 at the time of committing a crime and was sentenced to fixed-term imprisonment of not more than five years, the relevant criminal records shall be sealed up. If the criminal record is sealed, it shall not be provided to any unit or individual, except for the need of judicial organs to handle cases or the relevant units to make inquiries in accordance with state regulations. Units that inquire according to law shall keep the sealed criminal records confidential.