Coating on postharvest fruits is emerging as a new technique to extend the shelf-life of fruits. In this experiment, tangerine fruits were dipped in chitosan (CS) and chitosan/nanodiamond (CS/ND) (ND content was 2%) composite coating solution for 2~3 min. After drying, they were stored with the untreated group (CK) and commerial fresh-keeping agent (FA) treated group at 10 ± 3oC with a relative humidity of 65±10%. Changes of weight loss, ascorbic acid content, total soluble solids content, titratable acid content, internal CO2concentration and rotting rate of fruits were monitored. Moreover, the surface morphologies of peels and coatings of fruits were investigated periodically during storage. Results showed that CS/ND coating decreased the rotting rate of fruits during the whole storage, while CS coating was effective only during the first 7 days. Fruits with CS/ND coating showed higher content of absorbic acid and total soluble solids at the first stage of storage, but had higher content of titratable acid during the whole storage, compared to other groups. Moreover, fruit coated by CS or CS/ND also presented higher CO2concentration. These results revealed that CS/ND coating effectively extended the storage time of fruits and maintained their qualities. Micropores were observed on the coatings layers with the increasing storage time. Addition of ND into coating enhanced the stability, and delayed the appearing of the micropores, which leaded to the lasting effect of preservation.