Resulting　from　the　preferential　alignment　of　sediment　particles,　permeability　anisotropy　of　unconsolidated　strata　is　an　essential　parameter　for　natural　gas　hydrate　(NGH)　exploitation.　Fundamentally,　the　effect　of　mineral　particle　shape　and　pore-filling　NGH　on　the　permeability　anisotropy　are　considered　in　this　study.　A　simulation　with　combining　methods　of　particle　flow　code　and　computational　fluid　dynamics　is　conducted　to　construct　a　series　of　numerical　samples　and　calculate　the　anisotropic　permeabilities.　Different　particles　shapes　and　hydrate　saturations　are　preinstalled　in　these　samples.　It　is　firstly　proved　that　the　elongated　particles　have　little　effect　on　permeability　anisotropy.　Meanwhile,　the　preferential　alignment　of　plate-shaped　particles　is　the　main　reason　for　permeability　anisotropy.　In　principle,　the　difference　between　intermediate　orthogonal　axes　and　short　orthogonal　axes　of　plate-shaped　particles　makes　the　tortuosity　different　in　directions,　thus　inducing　the　permeability　anisotropy.　The　anisotropy　ratio　decreases　with　the　increase　of　hydrate　saturation,　which　is　caused　by　the　nonlinear　decline　of　main　channel　flow　resulting　from　the　thrombus-like　hydrate　particles.　The　results　provide　an　insight　into　the　formation　mechanism　of　permeability　anisotropy　and　display　potential　application　value　in　NGH　exploitation,　groundwater　environment　protection　and　geological　disaster　prevention.