Abstract There are currently three arguments in the treatment of business tax in Taiwan's integrated income tax system. They are the income tax expense argument, appropriation of net income of income tax argument, and income tax asset argument. Among them, the income tax expense argument is mainly adopted. The purposes of this study are, first, to examine the legitimacy of the regulations of the current financial accounting principles as well as the arguments of scholars and experts. Then we try to find a more perfect accounting treatment model. Finally, we study the current income tax law regulations to check if it is absolutely necessary to set up an imputation credit account outside the book of account. This study finds that the current system is not legitimate enough to fulfill the requirements of an idealized accounting treatment model. The nature of business tax in our integrated income tax system should depend on the attributive situation rather than judging its nature and accounting treatment by the above mentioned three arguments. Therefore, this study proposes an innovative argument entitled Income Tax Attribution Argument. The logic of this new system is primarily to analyze the attributes for income tax according to current tax law; then judge its nature by its attributive situation; finally, decide its accounting treatment in accordance with its nature. According to our current income tax law, there are at least seven categories of attributive situations. The differences among their natures are so large that we have to distinguish them. The mistake that the income tax expense argument makes is that it attempts to treat various accounting affairs by a single accounting concept and method. Part of the differences among their natures were mentioned in the appropriation of net income of income tax argument and income tax asset argument, but no further study appeared later. Therefore, this study tries to bring out a new method of business income tax based on the attributive situation. We examine the nature and accounting treatment method according to four aspects: business entity convention, ownership theory, classification definition, and matching principle. The result shows that it has more advantages, even though it is a bit complex, and hence is a more perfect accounting treatment model compared to the others. The Income Tax Attribution Argument proposed by this study lists the classification of applying deductible tax amount formally to record the unapplied deductible tax amount. This classification can replace the shareholders' account of unapplied deductible tax amount. Therefore, it is unnecessary to set up an imputation credit account outside the book of account as is done in the current income tax law regulations.