A very important challenge with regard to tax audits by their tax authorities is how to ensure timely completion. Infact very little exercise on a tax audit in Nigeria begins and ends within 12 months, most of them for many years before closing. This study examined empirically, the effect of tax audit practice on down south tax revenue generation in Nigeria. Both primary and secondary source of data was adopted and the data collected was analysed using linear regression analysis and multiple regression analysis with the aid of special package for social sciences (SPSS) version 21.0 with 0.71%, the empirical results indicate that the predictor variable of tax audit practice has positive effect on criteria variable of tax revenue in Nigeria. The study include that the exist a significant positive effect of desk audit on personal income tax. Based on the above, the study expressly make the following recommendations that cost and cost analysis between the value of tax verification and tax receipt tax that are expanded to be conducted before the tax authorizes. This is to ensure that the collection of taxes has been higher then the costs improving compliance. Tax administrators should not concentrate only on desk tax audit but also on field tax audit and back tax audit so as to block all leakages and increase the level of tax payers compliance