Tax policy towards industrial workshops is an important issue because industrial workshops in the country constitute an important part of the economy. The main source of income for the government, it must ensure that all possible strategies are used to maximize tax revenue. The statistical population considered for this study is industrial workshops with 10 employees and most of them are active in industrial towns in the country. Also, to examine the questions of this study, the model considered for testing is the threshold regression model with a smooth transition. The findings of this study showed that the nonlinear relationship between the variable of tax on the sales value of products produced by small and medium-sized industrial workshops and the added value of the products of those workshops was not observed and proven, and finally the results indicate that the coefficients of the influence of the variables of duties and indirect taxes, per capita production of small and medium-sized industrial workshops, and the formation of fixed capital on the variable of value added of these workshops are positive and significant. Accordingly, it is suggested that the tax organization, taking into account all aspects related to investment and production costs of the workshops in the provinces of the country, should apply tax laws and collect tax revenues from the sales value of products produced by these workshops. This, in addition to increasing tax revenues, can lead to a very significant and significant increase in the added value of these workshops.