Desertification process is a phenomenon of high environmental and social complexity because it embraces a significant number of indicators and variables that inter relate and that complement the comprehension of this process. One of the most useful and applied ways of the study of desertification verification is through the calculation of the Aridity Index (AI). This way, this present study uses that methodology to verify the situation of AI in Center-North region of Brazilian Semi-Arid. The aim was to investigate the variety of AI and its classifications during the period between 1961 and 2015, using temporal series of 30 years, expressed in the time interval of 2005, 2010 and 2015. It was possible to observe that therefore some changes in AI in many locations, where quantitative changes happened in the area, increasing mainly to the conditions of aridity aggravation, there was not the meaningful occurrence of alteration in the Desertification Tendency classification.