Improvement of tax system is the main condition of normal functioning and economic development of state. Tax system and, correspondingly tax policy is very important problem for a state of developed, developing or transition economy. In spite of level of development there are no countries without debates regarding tax system, its mechanism and management, tax policy and rates. This article covers just these matters, namely what tax burden should determine tax policy, what tax rates should determine certain tax in condition of such taxation. We present and analyze here statistic, pessimistic and optimistic concepts, as well as those of Laffer-Keynes and Abuselidze and their effects on business activity and output. The results of such effect clearly prove optimality of tax system, its mechanism and management, tax policy and rates. Key Words: Finance, State Budget, Tax Policy, Tax Burden, Optimal Taxation, Production Capacity.