Decentralized cryptocurrencies have emerged as an essential regulatory issue for governments since their introduction in 2009 and widespread use in recent years. These new technologies exist in the environment of blockchains and peer-to-peer networks, outside the supervision of central banks. Therefore, the absence of a centralized regulatory body, anonymity, the lack of universally accepted classification, valuation problems, and extreme fluctuations have created challenges and inconsistencies regarding the regulation of cryptocurrencies, especially in tax discussions. This has resulted in the lack of integration and disorder of laws and regulations, and tax inequality for cryptocurrency users. In a review of the framework of the European Union's approach to value-added tax and capital-gains tax on cryptocurrency trading with a descriptive-analytical method and the use of up-to-date library resources, it was found that tax regulators are focused on the areas of cryptocurrency speculation and brokerage activities. Taxes are levied on business operators, while other cases are exempted from tax. But the analysis of this approach showed that the tax challenges such as the exchange rate, anonymity and fair value of cryptocurrencies have not been paid attention to; Therefore, the results of this research revealed that things such as the use of the LIFO storage method in calculating the fair value of cryptocurrencies, the creation of an initial registration system for exchangers providing virtual asset services, the supervisory body of the special action group for the treasury of cryptocurrencies, and the system of trading contracts in order to prevent The anonymity of cryptocurrency transactions helps tax regulators in Iran not to face the aforementioned challenges.