In order to explore the effects of ⁶⁰Co-γ ray radiation on seed vigor of japonica rice in the cold region, 3 doses （220 Gy, 250 Gy, 280 Gy）were used to irradiate 6 japonica rice varieties, to analyze the changes in seed vigor of different varieties. The results indicated that, under the dose of 0~280 Gy, the radiation could inhibit the seed germination rate, bud length and root vigor index; the germination potential is different due to different varieties; there were significant differences in the radiation sensitivity of seed vigor among the tested varieties. Seed bud length was most affected by the main effect of radiation dose, V3 bud length was the largest, and V4, V2 and V5 bud length was greatly affected by radiation inhibition; the second was the effect of radiation dose on root vitality index, V3 root vitality index was the largest, V4 and V5 root vitality index were most affected by radiation inhibition; the third was the effect of varieties on germination potential, the germination potential of V3 and V4 was greater, the germination potential of V6 was the smallest; the fourth was the effect of variety × dose interaction factors on germination potential, radiation had a significant inhibitory effect on the germination potential of V2 and V3, and a significant promotion effect on the germination potential of V1, V5 and V4. The germination rate, bud length and root vigor index of V6 were the smallest, which would be the result of the combination of the characteristics of the variety itself and radiation inhibition. The results of this study could provide a technical reference for future research on radiation mutation of rice breeding in cold regions.