This paper evaluates the principles, relevance, and usefulness of Islamic banking law in implementing Islamic banks' administrative system. Islamic sharia law has become a source of law in several Islamic countries. Sharia law comes from the Islamic religion, which must be applied in many sectors, including the banking system. The goal is to improve kaffah Islamic teachings in aspects of life by adhering to the Koran, a concept to be applied to many systems. Although this banking system has become a fundamental law, studies are still needed to determine the relevance, principles, and application of Islamic banking law with application in the field to see the advantages and disadvantages. An in-depth data analysis process was carried out, which included data coding, critical interpretation, and evaluation that matched the findings with the discussion topic and determined the findings' validity and reliability. Based on the literature, the findings of this study confirm that Islamic banking law has been applied correctly in the context of administrative services in the field because of the effectiveness and vision of the ummah in the context of concepts, principles, and field application; assisting public financial services in Islamic countries.