The Gauss theorem points that the macro magnetic field is of no source in forms.In other words,it can be used as a criterion for judging the existence of magnetic monopole.But in the micro-world,the magnetic monopole can be found by means of testing the existence of the Berry-phase.A new style method was developed to discuss the possibility of the existence of magnetic monopole in micro area by comparing the Berry-phase and Hall effect of light.Based on the theories in macro and micro areas,a simple theoretical derivation was presented to probe into the possibility of the existence and conditions of “magnetic monopole”.