To study the effects of the two pruning treatments (girdling and ringing) on the growth of branches and accumulation of carbon-nitrogen metabolites in leaves of Carya illinoinensis, branches from 5-year-old grafted seedling of ‘Pawnee’ pecan were girdled with different widths (1 mm/2 mm/3 mm) and ringed with different circles (1 circle/2 circles/3 circles). The results showed that girdling and ringing inhabited the shoot elongation, but promoted the shoot radial growth. The contents of soluble sugar, starch, protein and the ratio of C/N in the leaf treated with girdling 3 mm were higher than other treatments and the control, but no significant differences were found in the treatment of girdling 2 mm. The contents of soluble sugar, starch and protein and the ratio of C/N in the leaf treated with ringing3 circles were the highest. Girdling and ringing might have effects on the trunk growth of Carya illinoinensis. The suitable pruning treatment of Carya illinoinensis is girdling 3 mm or ringing 3 circles.