The　high-rate　and　stably　efficient　nitrite　generation　is　vital　and　still　challenges　the　wide　application　of　partial　denitrification　(PD)　and　anammox　technology.　Increasing　attention　has　been　drawn　to　the　granulation　of　PD　biomass.　However,　the　knowledge　of　PD　granular　sludge　is　still　limited　in　terms　of　granules　characterization　and　mechanisms　of　biomass　aggregation　for　high　nitrite　accumulation.　This　work　reviewed　the　performance　and　granulation　of　PD　biomass　for　high　nitrite　accumulation　via　nitrate　reduction,　including　the　system　start-up,　influential　factors,　granular　characteristics,　hypothetical　mechanism,　challenges　and　perspectives　in　future　application.　The　physiochemical　characterization　and　key　influential　factors　were　summarized　in　view　of　nitrite　production,　morphology　analysis,　extracellular　polymer　substance　structure,　as　well　as　microbial　mechanisms.　The　PD　granules　exhibit　potential　advantages　of　a　high　biomass　density,　good　settleability,　high　hydraulic　loading　rates,　and　strong　shock　resistance.　A　novel　granular　sludge-based　PD　combined　with　anammox　process　was　proposed　to　enhance　the　capability　of　nitrogen　removal.　In　the　future,　PD　granules　utilizing　different　electron　donors　is　a　promising　way　to　broaden　the　application　of　anammox　technology　in　both　municipal　and　industrial　wastewater　treatment.　©　2023　Elsevier　B.V.