Fracture　flow　is　the　dominant　flow　in　many　cases　in　a　fractured　rock　mass,　which　behaves　more　heterogeneous,　anisotropic　and　irregular　than　porous　flow　because　of　the　complexity　of　the　fracture　networks.　Rock　mass　with　fracture　networks　is　commonly　represented　by　homogenized　continuous　models　to　reduce　the　impractical　computational　complexity.　In　this　paper,　a　density-reduced　equivalent　discrete　fracture　network　(E-DFN)　method　is　proposed　to　simplify　the　original　highly　dense　target　DFN　(T-DFN)　models.　An　equivalent　permeability　factor　is　derived　for　the　fracture　sets　in　the　simplified　E-DFN　models.　A　number　of　T-DFNs　with　different　fracture　patterns　are　stochastically　generated　and　fluid　flow　is　simulated　in　both　T-DFN　and　corresponding　E-DFN　to　test　the　effectiveness　of　the　proposed　method.　Results　show　the　permeability　similarity　of　the　two　DFN　systems　and　high　accuracy　of　the　proposed　E-DFN　method.　The　proposed　method　takes　the　advantage　of　permeability　similarity　of　DFN　systems,　and　it　significantly　reduces　the　computational　complexity　and　cost　while　the　characteristics　of　the　fluid　flow　such　as　heterogeneity,　irregularity,　and　discontinuity　in　highly　fractured　rock　mass　are　well　retained.　Because　of　the　statistical　equivalence　of　the　two　DFN　systems,　Monte　Carlo　simulations　can　be　used　to　optimize　the　equivalent　permeability　factor　and　to　achieve　more　accurate　and　reliable　results.