The　recent　research　on　high-density,　large-capacity,　nonvolatile　holographic　storage　in　photorefractive　crystals,　carried　out　at　Beijing　University　of　Technology,　is　reviewed　in　this　paper.　A　batch　thermal　fixing　technique　was　developed　to　overcome　the　volatility　of　a　large　number　of　multiplexed　holograms,　which　has　also　proved　to　increase　the　effective　dynamic　range　of　crystals,　hence　to　increase　the　storage　density.　The　key　of　this　technique　is　determination　of　the　inter-batch　optical　erasure　time　constant　that　is　much　longer　than　the　convenient　(intra-batch)　erasure　time　constant　of　the　crystal.　Disk-type　storage　is　proposed　to　increase　the　degree　of　spatial　multiplexing,　so　that　the　whole　volume　of　the　material　can　be　used　for　storage,　and　the　capacity　increases　remarkably.　Incorporating　batch　thermal　fixing　into　holographic　disk　storage　yields　to　a　track-division　thermal　fixing　(TDTF)　scheme　for　holographic　disk　storage　to　overcome　the　volatility　of　information　and　increase　the　storage　density　and　capacity　as　well.　Analyses　and　experimental　results　on　a　high　density　of　50　bits/mu　m(2)　(10　Gbits/cm(3))　show　that　high-density　huge-capacity　mass　storage,　indicated　by　storing　1　tera-bits　or　more　data　in　a　single　crystal　of　reasonable　size,　can　be　achieved　by　means　of　TDTF　holographic　disk　storage　scheme.