Abstract: The purpose of this work was to evalute effects of chitosan on keep-freshing of post-harvest apricot. The effects of 0.75g/L chitosan treatment on the post-harvest physiology and cell ultrastructure of apricot fruits were compared with the contrast. The results show that compared with contrast, 0.75 g/L chitosan treatment can reduce the rot ratio of fruit, alleviate fruit’s ripening and softening significantly, and maintaine higher total soluble solids content level.It can increase the activity of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)，but decrease the activity of polyphenol (PPO) and superoxide generation rate.It also can alleviate the degeneration of cell wall and chloroplast, and delay ripenning and senescence in the storage of apricot fruits.