In terms of structure, the ruling system of children hearing and trial is formed based on various models and the most well-known models at the world include welfare, legalism and participatory models. For example, in legalism model, the legality principle could be studied in the trial of children and juvenile. On the other hand, mediation in children trial could be studied in participatory model and in welfare model, presentation of social services for children could be studied such as allocation of social workers. In the Iranian novel law, especially in criminal procedure and Islamic Penal Code of 2013, special attention is paid to ruling trial and punishment of children and adolescents. Today, in the criminal law, specific attention is paid to the crimes and anti-social measures of children, so that some decisions are made in natural and formal rules that in addition to pay special attention to children, the way of punishment and the trials taken on this age group are taken in special way. Accordingly, some principles should be also considered in special trials for children, which could be principles such as the principle of innocence, the principle of the right to have attorney, the principle of law, the principle of the need for a special procedure for the investigation of child crimes, the principle of the proportionality of the system of responses or the character of offender child, the principle of secrecy of the proceedings, the principle of the need to pay attention to the personality of children, The principle of not accusing and the principle of silence. Each of the principles could be presented in the framework of fair trial principles. Hence, in field of trial models, welfare, legalism and participatory models could be referred, which could encompass the said principles.
