By two direct assumption methods and symbolic computation,we present two families of one-soliton solutions and a family of two-soliton solutions with some arbitrary functions for the three-dimensional Gross-Pitaevskii equation with time-space modulation.Then we investigate the dynamics of these matter-wave solitons in threedimensional Bose-Einstein condensates.We can see that the intensities of both one-solitons and two-solitons first increase rapidly to the condensation peak value,then decay very slowly to the background value.Thus these matter-wave solitons in three-dimensional Bose-Einstein condensates can remain for a sufficiently long time to be fully observed and modulated for real applications in todays experiments.