Fibrous　adsorption　material　with　amidoxime　(AO)　group　is　widely　considered　as　the　most　prospect　of　industrial　application　in　uranium　(U)　extraction　from　seawater.　However,　the　challenge　of　the　AO-based　adsorbents　is　that　the　utilization　of　AO　has　encountered　bottle-neck　of　less　than　1/100,　which　is　far　from　saturated　for　decades.　Herein,　we　construct　porous　structure　in　raspberry-like　nanofibers　(NFs)　with　rearranged　AO　groups　cyclic　imide　dioxime　(CID)　nanoparticles　(CID　NFs)　to　improve　the　AO　utilization　ratio　during　U　adsorption.　By　adjusting　the　size　of　the　CID　nanoparticles　in　NF,　the　area　of　the　functional　groups　can　be　maximum　exposed,　which　resulted　in　a　breakthrough　of　the　AO　utilization　ratio　with　high　adsorption　capacity.　In　simulated　seawater　with　a　U　concentration　of　330　ppb,　the　highest　AO　utilization　ratio　can　reach　1/31.　After　adsorption　in　natural　seawater　for　87　days,　the　adsorption　capacity　of　U　was　determined　to　be　11.39　mg-U/g-ads　with　AO　utilization　ratio　of　1/74.　Furthermore,　extended　X-ray　absorption　fine　structure　(EXAFS)　fits　and　nuclear　magnetic　resonance　(NMR)　spectra　suggested　that　the　mechanism　of　AO　bind　uranyl　ion　was　a　tridentate　binding　model　with　CID.　Density　functional　theory　(DFT)　computational　studies　proved　that　the　tridentate　binding　model　was　the　most　stable　combination.　Positron　annihilation　lifetime　spectroscopy　(PALS)　found　that　the　generation　of　smaller　freevolume　holes　in　CID　NFs　have　a　certain　cooperative　binding　in　space　on　U　adsorption.　The　CID　NFs　with　unique　nano　morphology,　and　special　CID　chemical　structure　provide　a　new　idea　and　potentiality　for　a　novel　design　of　U　adsorbents　in　future　U　extraction　from　seawater.