At the early Islamic era, Dirham and Dinar were two current coins in the society, thus, the holy lawgiver appointed them as a criterion for paying expiations, damages, and religious taxes. So, many decrees were based on the prevalent thought at that time upon these two coins. In the early Islamic centuries, Dirham and Dinar were known as gold and silver coins. There was always a ratio between them in terms of weight and value, usually, ten silver dirhams were equal to one gold dinar. As these two Islamic coins were put aside from daily exchanges, their ratios were gradually forgotten too. Gradually a wrong opinion was shaped based on this trend that each of these coins could be used separately as a criterion for paying religious debts, regardless of their original ratio.This trend first emerged in jurisprudence literature and then in legal texts and laws, as the legislation process based on jurisprudence began. This trend arose many problems in understanding and applying narrations and interpreting and executing some of legal terms, including law of blood money (dīya). Nowadays, while executing Islamic laws, we encounter some problems which would be solved by correcting this wrong trend. In this study, with the use of religious and historical texts, the nature and ratio between these two coins has been explained and their value ratio in all jurisprudence and legal issues established.