Abstract: Two-year-old field sweet cherry trees（Prunus avium L.‘Hongdeng’/Cerasus sachalinensis Kom.）were used to study the effects of different cutting back pruning degrees on characteristics of distribution of 13C and 15N，and as well as utilization of 15N. The results showed that the cutting back pruning promoted the carbohydrates to root system distribution at the new shoot growing stage. The extremely heavy cutting back pruning reduced the 13C distribution ratios to the leaves and new shoots respectively by 29.15% and 7.3%，and increased the distribution ratios to the large and fine roots respectively by 46.65% and 48.43% With the tree growing process，the 13C distribution ratios in the cutting back pruning treatment's leaves and new shoots were higher than that in the control. The 13C distribution ratios in the perennial branches decreased with the increase of the cutting back pruning intensity. The 13Cdistribution ratios in roots were the lowest in the moderate cutting back pruning and the highest in the extremely heavy cutting back pruning. The sequence of the 15N utilization ratios from high to low was the moderate pruning > the control > the extremely heavy pruning. The maximum difference of 15N utilization efficiency appeared at new shoot stop growing stage，and the 15N utilization ratios respectively were 6.91%，5.54% and 3.60% in the moderate，the extremely heavy cutting back pruning and the control. The 15N utilization ratios in the perennial branches decreased with the increase of the cutting back pruning intensity and that in leaves and new shoots increased with the increase of the cutting back pruning intensity.

Key words: sweet cherry, cutting back pruning, 13C, 15N, distribution, utilization