The　initiation　and　development　of　sand　liquefaction　has　been　demonstrated　to　be　closely　related　to　the　microscopic　fabric　evolution　in　previous　research.　The　evolution　of　force　chains　and　fabric　anisotropy　plays　a　critical　role　in　the　evolution　of　sand　liquefaction,　while　a　further　study　on　the　force　chain　length　and　the　fabric　anisotropy　of　the　strong　and　weak　force　chains　during　sand　liquefaction　is　still　needed.　To　this　end,　undrained　cyclic　biaxial　simulations　were　conducted　using　discrete　element　method.　Various　cyclic　stress　ratios　(CSR)　and　packing　densities　were　considered.　The　results　show　that　the　contact　and　mechanical　anisotropy　of　the　sample　increases　with　the　increment　of　CSR,　while　the　increase　of　anisotropy　is　mainly　attributed　to　the　strong　force　chains.　The　anisotropy　of　the　weak　force　chains　is　much　smaller　compared　to　that　of　the　strong　force　chains　and　it　varies　little　throughout　the　sand　liquefaction.　The　anisotropy　of　strong　force　chains　increases　obviously　with　the　development　of　sand　liquefaction,　which　is　further　demonstrated　to　be　related　to　the　growth　of　the　effective　stress　ratio.　The　strong　force　chain　length　was　calculated　as　the　number　of　particles　participating　in　the　transmission　of　strong　forces.　The　total　number　of　strong　force　chains　decrease　with　the　development　of　sand　liquefication,　while　the　relative　frequency　of　the　strong　force　chains　with　a　given　length　always　exhibits　an　exponentially　distribution　with　the　growth　of　force　chain　length　at　any　stage　of　sand　liquefication.