According to the band transport model theory,we establish the temporal evolution for dynamic equations concerning screening photovoltaic solitons in LiNbO_3 crystal in this paper.By using the finite difference method,we find that there exist large self-deflection bright and dark screening photovoltaic solitons in LiNbO_3 crystal,where the shape of the solitons becomes asymmetry ic with the increase of time.In addition,the absolute value of slope of the curve in deflection direction turns larger,while it ten...