The　method　for　investigating　the　holography　time　constants　in　two-center　holographic　recording　is　proposed.　The　effects　of　the　Fe　and　Mn　concentrations,　oxidization-reduction　state　and　intensity　ratio　I-R/I-UV　on　the　recording　time　constant　and　erasure　time　constant　in　doubly　doped　LiNbO3:Fe:Mn　crystal　are　theoretically　studied　by　using　the　numerical　method.　The　results　show　that　the　smaller　recording　time　constant　and　the　larger　erasure　time　constant　can　be　achieved　simultaneously　by　using　the　lower　Mn　concentration　and　the　larger　intensity　ratio　I-R/I-UV　in　multiplexing　holograms.