To evaluate residues dynamics of ethephon in banana,field test for ethephon residue in banana was conducted in Zhanjiang City,Guangdong Province.This experiment adopted the high ion chromatography and the new pretreatment process.The residues and degradation dynamics of ethephon in banana conformed completely to the equation of first-class reaction kinetic.the half-life of degradation for ethephon was 1.4 ~ 3.2 d in banana.According to the recommended dosage,the lowest residue in 70% mature banana whole fruit was 14.796 mg /kg,the lowest in banana pulp was undetected.Considered the data and MRL from all over the earth,this paper suggested that the maximum recommended residue limit was 2 mg /kg in banana.