ABSTRACT: The study aimed at identifying the effect of the legislative amendments on income tax law during the period (1996-2016) on the effectiveness of the tax system in Jordan, the studyuse the descriptive analysis, and concluded that there is no statistically significant effect of the change in GDP on the actual tax revenues, and there is no significant differences between the ratios of actual tax revenues to GDP, as well as the ratio of actual tax revenues to the general state revenues, and to the presence of statistically significant differences between the percentages of the overall compliance ratios during the sub-study periods, although they do not constitute a general trend for improvement.The study recommends minimizing the amendments to tax legislation to achieve stability in tax legislation and to encourage investments, and the amendments should focus on combating tax evasion and improve tax collection procedures and to avoid increasing the tax rate because it increases the burden of obliged taxpayers and compensates tax evaders.