Sensitive　detection　of　dopamine　(DA)　is　essential　for　the　diagnosis　of　nervous　system　diseases.　Herein,　a　nanozyme-based　colorimetric　platform　for　DA　determination　was　proposed.　Using　an　imine-type　covalent　organic　framework　(COF-TD)　as　a　host　matrix,　a　nanozyme　(AgNPs@COF-TD)　was　fabricated　by　anchoring　silver　nanoparticles　(AgNPs)　on　the　surface　of　COF-TD　via　in　situ　reduction　of　silver　ions.　Various　characterization　results　confirmed　the　successful　synthesis　of　flower-like　AgNPs@COF-TD　with　surface-anchored　AgNPs,　which　could　expose　more　active　sites.　The　as-prepared　AgNPs@COF-TD　exhibited　satisfactory　oxidase-mimicking　activity　with　a　low　Km,　which　could　catalyze　the　oxidation　of　colorless　3,3　＇,5,5　＇-tetramethylbenzidine　(TMB)　to　blue　oxidized　TMB　(oxTMB)　with　significant　absorbance　at　657　nm.　The　introduction　of　DA　not　only　reduced　blue　oxTMB　to　colorless　TMB　but　also　competed　with　TMB　for　the　active　sites　of　AgNPs@COF-TD,　making　a　significant　decrease　in　absorbance.　Therefore,　a　label-free　sensing　strategy　based　on　the　oxidase-mimicking　activity　of　AgNPs@COF-TD　was　successfully　established　for　the　colorimetric　detection　of　DA,　with　a　detection　limit　down　to　0.2　mu　M.　The　practical　applicability　of　this　assay　was　further　validated　by　analyzing　DA-spiked　human　urine　samples.　This　work　provided　a　facile　approach　to　prepare　COF-based　nanozymes,　and　demonstrated　their　great　potential　in　colorimetric　detection　and　bioanalysis.