Abstract：The effects of N+ ion implantation on diploid rice and inducement of polyploid rice were researched, using the 3 sets of diploid rice as the materials and N+ ion beam as the mutagenic agent. The results showed that the effectiveness of N+ ion with over-low energy on the diploid rice depended on the types of materials and the dosage of N+ ion. The effects on inducement of autotraploid rice after N+ ion implantation were very obvious, and the degree of effects were determined on the three factors, the dosages of N+ ion implantation, the time of colchicine inducement and the genetic background of the materials. In the experiments of the colchicine inducement to the materials for 24 h, the ion dosage of 6.76×1016 N+/cm2 showed better induced results, but in the experiments of the colchicine inducement to the materials for 48 h,the better results ,selecting easily autotetraploid rice, showed in the ion dosage of 0.52×1016 N+/cm2.The materials with autotetraploid characters have been obtained by selecting in the 2 or 3 generation and the karyotype analysis.