The research aims to analyze and measure the impact of investment spending on the national income levels of Iraq, and the Autoregressive Distributed Delay Periods (ARDL) model was used to find out the effect of the relationship between the independent variable (investment spending). And the dependent variable (national income) using a short-run relationship test coefficients, Bound test, and long-run coefficients. In order to verify the results, a time series extended from 2005-2020 was relied upon. The research reached a set of results, the most important of which was the presence of a positive impact of investment spending on national income in the long term. In addition, there is a positive effect of investment spending, as an increase in its value by one unit leads to an increase in national income by 0.045 million Iraqi dinars, assuming the constants of other factors (consumer spending, government spending and foreign trade). The results indicate that there is no A long-term relationship between investment spending and national income, since the probability of it is greater than (5%), as the probability of it was (0.3200), i.e. 32%. And this applies with the reality of the Iraqi economy, as the increase in investment spending does not lead to an increase in national income. Because investment spending contains a large degree of deviation from the required achievement. Consumer spending than public spending. And follow control policies in order to put an end to the deviation in public spending.