In this paper, forecasting error for state tax revenues is assessed. For this purpose, using the regression equation, statistical index, and mean percent error, root mean square error, mean absolute percent error and error analysis of tile inequality coefficients are applied on anticipated revenue from taxes on legal entities, income taxes, wealth tax, taxes on imports and taxes on consumption and sales during the years from 1350 to 1385. The results show that over the time period in this research, estimated income tax, wealth tax, taxes on imports and taxes on consumption and sale exceed the actual (optimistic) and the estimated tax on juridical persons is lower than actual level respectively. Also, the anticipated tax of legal entities, income taxes, taxes on imports and taxes on consumption and sale have nonsystematic error and forecast error of wealth tax has been systematic. Efficiency analysis to predict shows that the error predicted none of the pattern and trend of tax revenues over time.