In this study a MATLAB program to interpolate magnetic data using the inverse square distance approach and separate the regional/residual anomalies by the upward continuation method is developed. The application of this technique in combination with the spectral analysis and 2.5D modeling to the aeromagnetic anomaly of the Mimbi area in southern Cameroon has led to a better understanding of the stratification of the deep and near surface structures, which are sources of the observed anomalies. The maps obtained from filtering show that within the magnetic quiet zone, there is a high negative circular elongated anomaly, which seems to represent an intrusion of a magnetic body within the metamorphic rocks of the region. Two S-N profiles are drawn on the total and residual aeromagnetic anomaly maps respectively. The data sets derived from these profiles made it possible through a program written in MATLAB to have on one hand, the spectra of energy and on other hand, the depths of the sources of observed anomalies. Two 2.5D models of the subsurface structures have been proposed along the profiles P1 and P2, which were drawn on the residual map, obtained after an upward continuation up to 8.3 km. The 2.5D models obtained show a magnetic body, with a signature suggesting two masses close to opposite polarity, which characterize the iron-bearing formations.