从理论上讲，为了保持税负公平和增值税抵扣链条的完整，所有纳税人都应当实行规范的增值税，执行凭发票扣税的制度。然而，从世界各国税收征管实践看，众多的小企业由于会计核算不健全，难以执行规范的增值税制度。因此，在既保证税负公平又追求征管效率的原则下，几乎所有实 In theory, in order to maintain a fair tax burden and the completeness of the VAT deduction chain, all taxpayers should implement a standardized VAT and implement a tax deduction system. However, from the tax collection and management practices of all countries in the world, many small-sized enterprises are unable to implement the standardized value-added tax system because of their unsound accounting practices. Therefore, under the principle of ensuring a fair tax burden and pursuing the efficiency of collection and management, it is almost all reality