The　gas-solid　method,　discovered　in　recent　years,　has　been　shown　to　have　the　potential　to　fabricate　dense　MgB2　bulks.　In　this　study,　we　aimed　to　investigate　the　dominant　regulation　mechanism　underlying　the　superconducting　properties　and　microstructures　of　MgB2　bulk　obtained　from　the　gas-solid　method.　To　this　end,　we　utilized　nano　computed　tomography　(nano　CT)　and　transmission　electronic　microscopy　to　examine　the　structure　of　the　MgB2　bulk　at　the　micrometer　and　nanometer　scales,　respectively.　Nano-CT　results　revealed　that　the　application　of　a　mold　during　the　gas-solid　process　can　significantly　reduce　the　amount　of　holes　present　in　the　sample.　Furthermore,　the　reticular　hole　structure　can　be　almost　completely　eliminated　through　this　modification.　Such　a　change　can　account　for　the　remarkable　increase　in　superconducting　connectivity　(Af　value)　observed　in　the　sample　with　a　mold.　Additionally,　we　found　that　different　B　powders　can　lead　to　vastly　different　MgO　impurity　particle　sizes　and　distributions　at　the　nanometer　scale.　This　finding　can　explain　the　differing　Jc　(B)　values　and　pinning　forces　observed　in　the　corresponding　samples.　Overall,　our　correlation　analysis　between　the　structure　and　superconducting　properties　provides　valuable　insights　into　the　possible　regulation　mechanism　of　MgB2　bulk　obtained　from　the　gas-solid　method.　These　findings　may　assist　researchers　in　further　improving　the　performance　of　MgB(2　)bulks.