An　enormous　challenge　for　the　harmonic　state　estimation　of　distribution　networks　is　how　to　perceive　the　complex　and　varied　dynamic　harmonics　in　a　higher　resolution　method.　To　solve　this　problem,　this　article　proposes　an　interval　dynamic　harmonic　high-resolution　state　estimation　method　for　distribution　networks　based　on　multisource　measurement　data　fusion.　First,　to　obtain　the　typical　high-resolution　harmonic　measurement　information　of　distribution　networks　under　the　limited　measurement　devices,　a　selection　method　for　the　measurement　sites　of　high-resolution　power　quality　monitoring　devices　(PQMDs)　is　proposed　based　on　the　harmonic　electrical　distance.　On　this　basis,　a　multisource　data　fusion　method　based　on　the　time　period　inclusion　index　is　proposed　to　establish　hybrid　interval　measurement　datasets.　Second,　to　improve　the　efficiency　of　interval　dynamic　harmonic　state　estimation,　the　interval　intermediate　variables　are　introduced　to　construct　the　three-stage　hybrid　interval　harmonic　measurement　equations.　Finally,　an　interval　dynamic　harmonic　high-resolution　state　estimation　method　is　proposed　based　on　the　predictor-corrector　method,　the　IGG-III　robust　interval　Kalman　filter　(IGGIII-RIKF)　is　used　as　the　predictor　stage,　and　the　forward-backward　interval　constraint　propagation　(FBICP)　algorithm　is　used　as　the　corrector　stage　to　realize　interval　dynamic　harmonic　high-resolution　state　estimation.　The　effectiveness　and　feasibility　of　the　proposed　method　have　been　demonstrated　on　the　IEEE　33-bus　system　and　the　IEEE　118-bus　system.　©　2025　IEEE.