单一税自提出后,引发了不断的争论,但进入21世纪后,大量的转轨国家实施了单一税改革.究其原因,在转轨国家有限的税收征管水平下,非理想的综合所得税远不能发挥其应有的效应,而单一税则由于其自身特点,在提高税收收入,降低税制效率损失、增强税制公平性、提高国际竞争力等方面具有正面效应,适应了转轨国家的需要.“,”Flat tax has brought continuous disputes after its presence,but still in the 21st century,it has been adopted by many transitional countries.The reasons are as follows: under the circumstances of limited tax administration in transitional countries,no ideal comprehensive income tax can play its full role at all while flat tax has demonstrated its positive effects in increasing tax revenue,decreasing tax system's efficiency loss,reinforcing tax system's equity and enhancing international competitiveness,which just address the needs of the transitional countries.