In the context of the nearly-free-electron model, we apply a full non-local model pseudopotential theory to investigate the temperature dependence of the electronic magnetic susceptibility for liquid lithium and sodium. In contrast to previous and recent theoretical calculations, we adopt the accurate generalized non-local model pseudopotential of Li et al to simulate self-consistently the liquid structure factors of both metals. Within the nearly-free-electron theory, we find that the ion-potential alone is not sufficient to explain the temperature trend of the electronic magnetic susceptibility. Nonetheless, by seriously considering the many-body electron-electron exchange correlation and analysing its temperature change, we are able to understand certain features of the susceptibility as observed in recent experiments. The limitation of our theoretical model will also be indicated.