A high sensitive electrochemiluminescence（ECL） sensor was established for the determination of chloramphenicol（CAP） in water based on magnetic molecularly imprinted technique and strong inhibitation of CAP on ECL signal of Ru（bpy）2+3/tripropyl amine system.Chloramphenicol molecularly imprinted membranes（MIPs） were synthesized on the surface of Fe3O4-Au magnetic nanoparticles by self assembly，using Fe3O4-Au magnetic nanoparticles as carriers，4 aminothiophenol（4-ATP）and 2-acrylamido-2-methylpropane sulfonic acid（AMPs） as binary functional monomers，ethylene dimethacrylate（EGDMA） as a cross linking agent and ammonium persulphate（APS） as an initiator.The magnetic glassy carbon electrode（MGCE） modified with the magnetic molecularly imprinted polymer was used as an ECL sensor for CAP.Under the optimal conditions，there was a good linear relationship for CAP with ECL quenching values of the system in the concentration range of 0.010-100 ng/L，with a correlation coefficient（r） of 0.998 0 and a detection limit of 0.010 ng/L.Results showed that the sensor has a good application prospect in the determination of CAP with advantages of high sensitivity，good selectivity and wide linear range.