A　batch-thermal　fixing　technique　is　present　to　increase　the　effective　dynamic　range　of　photorefractive　crystals,　hence　to　increase　the　storage　density.　The　parameter　M#batchis　defined　for　quantitatively　characterizing　the　available　enhancement　in　storage　capacity　of　a　batch-thermal　fixing　holographic　storage　system.　The　dynamic　range　corresponding　to　the　number　of　batches　is　calculated　and　compared.　The　improvement　of　the　dynamic　range　of　a　batch-fixing　holographic　storage　system　is　dependent　on　the　difference　of　inter-batch　and　intra-batch　optical　erasure　time　constants.