To study the temporal properties of the low-amplitude bright spatial solitons in biased two-photon centrosymmetric photorefractive crystals,we present the expressions of the time-dependent spatial charge field and the equation of the spatial profile for the bright solitons as time evolve.The numerical results show that solitons width decreases monotonically to a minimum value toward steady state with the increasing of time.The higher the ratio of soliton peak intensity to the dark irradiation intensity,the narrower the width of bright solitons under within propagation time.The input beam can evolve the steady spatial solitons under different time.The results are benefit for improving the theory of spatial photorefractive solitons.