More and more attentions have been focused on design and synthesis of novel metal-organic framework/graphene oxide (MOF/GO) composites with unique performance.Zirconium-porphyrin MOF (PCN-222) is in-situ synthesis with the existence of GO with-COOH group to artfully fabricate a PCN-222/GO composite.This composite can be employed as functional material to modify the working electrode.Thanks to excellent electrical conductivity of GO,abundant mesoporous channels and numerous Zr(Ⅳ) metal sites of PCN-222,this composite can immobilize a large amount of aptamer through strong π-π stacking interaction and high affinity between phosphate group of aptamer and Zr(Ⅳ) site of PCN-222 simultaneously.Hence,an ultra-sensitive electrochemical aptasensor based on PCN-222/GO composite can quantificationally detect trace chloramphenicol with limit of detection of 7.04 pg/mL (21.79 pmol/L)from 0.01 ng/mL to 50ng/mL by electrochemical impedance spectroscopy even in real samples.Meanwhile,this fabricated aptasensor reveals good repeatability,outstanding selectivity and preferable long-term storage.This research provides a useful approach to construct MOF/GO composites for fabricating electrochemical aptasensors in the electrochemical detection field.