The study presents rebuilding QSAR investigation on 12 Anticancer Schiff-base ligands that have an activity against prostate cancer. The geometries of the studied compounds were optimized first at level (MM+) by molecular mechanics force field theory and then at level (AM1) by semi- empirical theory. QSAR model includes some Molecular descriptors, regression quality indicates that these descriptors provide valuable information and have significant role in the assessment of the activity of Schiff-base ligands. Several models for the prediction of biological activity have been drawn up by using the multiple regression technique. Four models with R2 ranges from 0.98-0.99 were predicted. A model was used to improving a predict the data the anticancer activities, shown it a better predictive equations and the agreement between the observed and the predicted values was excellent. Study has shown that the biological activity of the studied compounds affected by C=N properties.