One of the evidences to prove a criminal case is the judge's knowledge. In criminal cases, the evidence is not ready in advance and after the criminal event, one should seek to collect them and one of the important factors of judge knowledge is new tools. In the present paper, an attempt has been made to examine it from the point of view of jurisprudence and criminal law. This paper is descriptive and analytical using the library method. The findings indicate that both jurisprudentially and legally, new tools such as expert and forensic theory, laboratory data and electronic evidence play an important role in the knowledge of the judge. New tools are a suitable source of knowledge for the judge and with the help of new tools, results can be achieved; either it causes the knowledge of the judge, or at least it creates a reasonable and conventional suspicion and provides the conscience of the judge. According to the dynamics of Islamic jurisprudence, in cases such as the presumption juris tantums, which is based on evidence to prove a claim, it is possible to use the valid findings of any era in accordance with the subject and ruling, among these findings are modern tools. When new tools conflict with the presumption juris tantums or other persuasive evidence, it is these new tools that take precedence over the presumption juris tantums since they have greater discovery and they are more reliable than other persuasive evidence.