Abstract: The aims were to investigate radiation effects of ⁶⁰Co-γ ray on the leaf morphogenesis of mutant strains in Fagopyrum dibotrys, and evaluate the stress-resistance of the different strains. The author observed leaf structures of control and mutants under the optical microscope and the scanning electrical microscope, and preliminarily evaluated the stress- resistance by the principal component analysis and subordinate function. The red stem strains were significant different from the green ones in leaf structures. Compared with the green stem strains, the leaf thickness of red stem strains decreased by 18.63% , and the thickness of the upper epidermis tissue increased by 18.94%; the thickness of palisade tissue and sponge tissue decreased by 26.96% and 13.74%, respectively; the average length of stomata increased, and the density decreased. There were no significant differences in anatomical structures between the red-leaf and green-stem strains. Only the average length of stomata increased, and the density decreased. Five parameters including the sponge tissue thickness, the stomata density of the lower epidermis, the upper epidermis thickness, the sponge texture thickness and the tightness of leaf tissue structure were screened out by the principal component analysis to assess the stress resistance. A subordinate function was used to rank their stress resistance, and the order was: green stem＞red leaf＞red stem. ⁶⁰Co-γ had an apparent radiation effect on leaf structure of Fagopyrum dibotrys, and the different mutant strains varied in stress resistance. This study provided the theoretical basis for plant breeding.