The　development　of　biosorbents　with　high　capacity,　good　stability　and　environmental　friendliness　has　emerged　as　a　significant　objective　in　Uranium　Extraction　from　Seawater　(UES).　Herein,　we　synthesized　a　novel　biosorbent　material　with　a　complex　reticular　structure　by　simply　cross-linking　polyethyleneimine　(PEI)　and　poly　(allylamine　hydrochloride)　(PAH)　onto　gelatin　(GEL)　forming　a　biosorbent　(GEL/PEI/PAH,　GPP).　The　prepared　biosorbent　showed　excellent　performance　with　a　maximum　adsorption　capacity　of　1340.25　mg/g　in　solution.　Furthermore,　GPP　exhibited　impressive　reusability,　maintaining　92.6　%　adsorption　capacity　and　92.8　%　elution　rate　after　7　adsorption　-　desorption　cycles.　The　main　adsorption　mechanism　of　GPP　is　attributed　to　ligand　complexation　reaction　of　amino　groups　on　PEI　or　PAH　and　hydroxyl　as　well　as　carboxyl　groups　on　gelatin　amino　acids　for　uranyl.　Notably,　GPP　displayed　good　selective　adsorption　capacity　for　uranium,　the　adsorption　capability　was　4.4　mg/g　after　15　days　of　immersion　in　real　seawater.　These　findings　show　the　potential　applicability　of　biosorbent　GPP　for　efficient　uranium　extraction　from　seawater.