The　traditional　power　flow　algorithm　of　distribution　network　is　mainly　based　on　the　forward　and　backward　algorithm,　the　complexity　of　the　algorithm　increases　sharply　and　it　is　difficult　to　expand　new　model　when　the　harmonics　and　three-phase　imbalance　are　comprehensively　considered,　and　the　convergence　of　the　algorithm　is　not　good　enough　when　the　type　of　source　changes.　Based　on　three-phase　fundamental　wave　power　flow　of　Newton-Raphson　method　and　three-phase　harmonic　admittance　matrix,　a　three-phase　power　flow　paradigm　algorithm　of　distribution　network　is　proposed,　which　comprehensively　considers　power　quality　problems　and　is　suitable　for　various　network　structures.　The　efficient　generation　and　random　access　method　of　three-phase　harmonic　admittance　matrix　and　three-phase　fundamental　wave　power　flow　matrix　of　Newton-Raphson　is　constructed　by　comprehensively　using　matrix　transformation　operations　such　as　matrix　inner　pro-duct,　matrix　index　and　incidence　matrix.　On　this　basis,　the　structure　of　three-phase　harmonic　admittance　matrix　is　updated　combining　with　transformer　and　other　models,　and　a　flexible　and　efficient　three-phase　harmonic　power　flow　algorithm　is　established.　OpenDSS　is　used　to　verify　the　accuracy　and　validity　of　the　proposed　algorithm　in　IEEE　14-bus　system.　The　proposed　algorithm　and　the　traditional　forward　and　backward　algorithm　are　compared　in　IEEE　123-bus　system,　it　is　verified　that　the　proposed　algorithm　can　improve　the　efficiency　and　deal　with　the　ring　network.　©　2022,　Electric　Power　Automation　Equipment　Press.　All　right　reserved.