The　potential　of　the　partial　denitrification　granular　sludge　(PDG)　has　been　highlighted　for　achieving　high　nitrite　(NO2　--N)　production.　However,　there　remain　bottlenecks　regarding　satisfactory　stability　and　NO2　--N　production　rates　(NPR).　In　this　study,　we　comprehensively　explored　the　physicochemical　characteristics　and　spatiotemporal　succession　of　the　microbial　community　inside　the　aggregates,　cultivated　under　multidimensional　shear　stress　with　horizontal　mechanical　agitation　and　vertical　hydraulic　mixing　in　a　continuously　up-flow　reactor.　High-rate　NO2　--N　production　with　an　NPR　of　2.66　kg　N/m3/day　was　achieved,　far　exceeding　the　currently　reported　value,　accompanied　by　a　relatively　stable　nitrate-to-nitrite　transformation　ratio　of　72%　and　satisfactory　settleability　without　sludge　flotation　and　blocking.　Interestingly,　the　morphological　structure　of　PDG　spontaneously　changed　to　be　much　more　pleated　at　the　outer　edge.　This　provided　sufficient　attachment-growth　sites　and　surface　area　for　functional　bacteria　(Thauera),　exhibiting　a　capability　of　NO3　--N　reduction　much　higher　than　that　of　NO2　--N　at　the　level　of　the　genes.　They　were　rapidly　enriched　with　proportion　increasing　from　36.8　to　67.4%　in　56　days.　These　spatiotemporal　structures　and　microbial　distribution　provide　an　extra　opportunity　to　select　specific　bacteria　for　high-rate　NO2　--N　production　and　treatment　of　high-strength　nitrate-containing　wastewater　by　combining　them　with　Anammox.