Abundant　natural　fractures　(NFs)　in　hot　dry　rock　(HDR)　reservoirs　serve　as　a　crucial　element　in　hydraulic　fracturing　technology　and　reservoir　production.　Nevertheless,　the　interaction　mechanism　between　hydraulic　fractures　(HFs)　and　natural　fracture　networks　(NFNs)　remains　poorly　understood.　This　study　combines　the　novel　hydro-grain-based　model　(hydro-GBM)　and　discrete　fracture　network　(DFN)　model　to　investigate　the　effects　of　in-situ　stress,　fracture　number,　and　fracture　length　on　hydraulic　fracturing　behaviors　in　mineral-scale　granite　with　NFNs.　Results　indicate　that　as　the　complexity　of　NFs　increases,　the　stress　shadow　effect　is　amplified　during　HF　propagation,　while　the　spatial　arrangement　of　NFs　governs　the　propagation　of　secondary　paths.　Additionally,　a　downward　trend　is　observed　in　average　activity　levels　of　acoustic　emission　(AE)　events　and　proportions　of　large　events　within　NFs　and　matrix.　Damage　and　activation　degrees　in　both　NFs　and　matrix　decrease　with　an　increase　in　the　number　of　NFs.　The　inability　of　main　hydraulic　paths　to　propagate　over　long　distances　can　be　attributed　to　the　dispersion　of　fracturing　fluid　and　the　rapid　decay　of　pressure　within　densely　distributed,　short　NFs.　These　numerical　findings　shed　light　on　the　process　of　HFs　activating　NFNs　and　provide　valuable　insights　for　enhancing　heat　extraction　efficiency　in　HDR　reservoirs.　©　2024