To investigate the effect of N-butanol treatment on proline metabolism of Hami melon fruits in cold tempera-ture，the fruits of Xizhou Mi 25 hao' Hami melon were soaked in N-butanol solution at the volume fraction 1 .0% and 0% for 30 min as the treated and control group， and the Hami melons were placed at (3 +0.5) C for 42 d. Samples were taken every 7 d. The chilling injury symptoms of Hami melons leaving low temperature to room temperature were recorded and the chilling injury index was counted, and the related indexes of proline metabolism were measured. The results showed that N-butanol treatment significantly (P< 0.05) suppressed the increase of chilling injury index at 35 d and 42d in Hami melons compared with the control group, and reduced the chilling injury symptoms in the later storage period, signifcantly increased the proline content (except 7 d) and △'-pyroline-5 -carboxylate synthase (P5CS) activity(except 21 d) and the relative gene expression as well as the activity of omithine (OAT) at 35-42d in storage, and sig-nificantly decreased proline dehydrogenase (ProDH) activity (except at 14 d) and relative gene expression at 28 and 42 d of storage (P<0.01). It indicates that N-butanol treatment maintained higher proline content significantly by increasing the activity and relative expression of the corresponding genes of CmP5CS and CmOAT， which was the key enzymes of proline synthesis, and the activity and gene expression of CmProDH was decreased， which reduced the chilling injury index and alleviated the symptoms of chilling injury in Hami melons， which was more effective treatment in improving the low temperature tolerance of Hami melon cells and maintaining better fruit quality.