The issue of evidence to prove the claim is one of the issues raised in the field of criminal procedures. Although in principle, there are some similarities between civil and criminal proofs, the criminal ones have unique characteristics that distinguishe them from lawsuit proofs. The evidence and discovering the truth are the main elements of criminal proceedings. Based on jurisprudence and law, it can be said that the basic pillar of settling claims is to discover the truth based on evidences. In jurisprudential and legal texts, the judge has been obliged to settle the lawsuits and make judgement based on truth. This authority has been given to judge to discover the truth and the authority is a requirement of proceeding in civil and criminal proceedings. The purpose of present study is to explain the statuse of judge knowlege to discover the truth. The present study has analyzed the status of judge knowlege in criminal jurisprudence and judicial procedure through descriptive analytical methods. Findings indicate that the rule of prohibition of acquiring reason in judge role is necessary to obtain the evidences and discover the truth. The role of judge cannot be ignored in discovering the truth in civil, legal, jurisprudential and judicial procedures. The result of study shows that the knowlege of judge in Islamic Penal Code is considered as a criteria to prove criminal claims along with other evidences.