Abstract: In order to study the temporal behavior of screening gray spatial solitons in biased one-photon centrosymmetric and non-centrosymmetric photorefractive crystals, the expressions of time-dependent space-charge field and dynamical evolution equation were deduced based on one-photon centrosymmetric and non-centrosymmetric photorefractive effect. The temporal behavior of the intensity profiles and the intensity full width at half maximum(FWHM) of gray solitons were studied by numerical method. The results indicate that, when the ratio between the soliton peak intensity and dark irradiance is larger, the FWHM of solitons first decreases to a minimum and then increases to a constant value; when the ratio between the soliton peak intensity and dark irradiance is smaller, the FWHM of gray solitons decreases monotonously with the increase of time toward steady state. Dynamical evolutions of the grey spatial solitons are simulated numerically at different time. Centrosymmetric and non-centrosymmetric gray solitons have the similar temporal properties.