Abstract: This article investigated the effect of pre-harvest bagging combined with low-concentration ethephon treatment on ethylene degreening behavior of mandarin fruits. The early ripening mandarin fruits from Beibei of Chongqing were bagged with yellow single-layer fruit bags before harvest. After harvest,the fruits were divided into six groups in this experiment,the control group(CK),the ethephon-degreened fruit(ETH,1000 mg/kg),bagging+0 mg/kg ETH,Bagging+250 mg/kg ETH,bagging+500 mg/kg ETHand bagging+1000 mg/kg ETH,respectively,and all the fruits were stored at 20 ℃ after treatment. The results indicated that with the extension of the storage period,bagging combined with ethephon treatment could better improve the color of early ripening mandarin fruits. After 6 days of storage,bagging+250 mg/kg ETH treatment,bagging+500 mg/kg ETH treatment and bagging+1000 mg/kg ETH treatment significantly improved the chromatographic parameters(a^* and a^*/b^*)of the fruits(P<0.05). Throughout the storage period,bagging+250 mg/kg ETH treatment delayed the increase of the decay rate and browning index successfully and maintained the firmness of the mandarin fruit,besides,it had no adverse influence on the soluble solid content and V_C content.In addition,pre-harvest bagging treatment on the total free amino acid content of mandarin fruits didn’t change significantly compared with the control group when harvesting(P>0.05),nordid affect the flavor adversely. But it could increase the content of the arginine acid of mandarin fruits which was related to aging and disease resistance. Based on the results mentioned above,not only the pre-harvest bagging combined with low-concentration ethephon(bagging+250 mg/kg ETH)can improve the degreening behaviors of mandarin fruits,reduce the problems of rot and browning of pedicles caused by conventional ethylene degreening treatment,but also this technology is easy to operate. Therefore,it has certain application prospects in the citrus industry.