Dimer　problem　for　three　dimensional　lattice　is　an　unsolved　problem　in　statistical　mechanics　and　solid-state　chemistry.　In　this　paper,　we　obtain　asymptotical　expressions　of　the　number　of　close-packed　dimers　(perfect　matchings)　for　two　types　of　three　dimensional　lattice　graphs.　Let　M(G)　denote　the　number　of　perfect　matchings　of　G.　Then　log(M(K2×C4×Pn))≈(-1.171n-1.1223+3.146)n,　and　log(M(K2×P4×Pn))≈(-1.164n-1.196+2.804)n,　where　log()　denotes　the　natural　logarithm.　Furthermore,　we　obtain　a　sufficient　condition　under　which　the　lattices　with　multiple　cylindrical　and　multiple　toroidal　boundary　conditions　have　the　same　entropy.　©　2015　Elsevier　B.V.　All　rights　reserved.