In order to study biological effects of,12,C,6+, heavy ions irradiation on ,Allium fistulosum, L,., the dry seeds were treated by ,12,C,6+, heavy ion beam with different doses. Obvious "parabola" trends were observed in the characteristics of germination rate and height of ,Allium fistulosum, L. seedling when irradiated doses increased. With irradiation of an appropriate dose of ,12,C,6+, heavy ion beam, 30Gy, the germination rate of ,Allium fistulosum, L. is increased and the seedlings can resist drought and lodging, and grow better than the control. At the same time, the formation frequency of micronucleus and chromosomal aberration were surveyed in root-tip cells. The highest formation frequency of micronucleus and chromosomal aberration treated with 180Gy could reach to 9.09% and 10.03% respectively. This study laid the basis for further work on breeding and improvement of ,Allium fistulosum, L,., irradiated by ,12,C,6+, heavy ion beam.