The best way to study the subsurface geothermal potential is by directly measuring the heat flow and temperature from boreholes. However, heat flow and temperature data are not uniformly distributed and not consistently deep; thus they are not enough in inferring deep thermal distributions. In this case, Curie depth isotherm may provide the deep thermal distribution which cannot be obtained otherwise. Estimation of Curie isotherm can be accomplished by assuming either a statistical ensemble of homogeneous sources or even a fractal sources distribution. The Curie isotherm, in combination with heat flow and temperature distribution data, may provide reasonable geological results, which can be used for further detail exploration. In order to assess the geothermal potential of the region, we have estimated the Curie isothermal surface of the Southern Italy trough spectral analysis. Spectral analysis in the Southern Italy suggests that the Tyrrhenian Sea is underlined by Curie isotherm that ranges from less than 10 km to 20 km, whereas the Apennines are characterized by relatively deep Curie isotherm. This variation is also consistent with the existing heat flow and temperature data, which shows high heat flow over the Tyrrhenian Sea and low heat flow values over the Apennine, with some local hotspots. Both the Curie depth results and heat flow data indicates that the Southern Italy is a promising area for further geothermal resources exploration and exploitation.