Abstract: Common bean(Phaseolus vulgaris L.) is one of the important crops in China and the world.Its various appearances, relative small genome size, short life cycle, and a close phylogentic relationship with soybean, make it an important genetic resource for studying gene function in legume.Aiming to create rich genetic variations, we exposed seeds of Golden Hook to ⁶⁰Co γ radiation at a dosage of 200 Gy, then observed their phenotypes at M₃ generation, and estimated the phenotypic variations of quantitative traits taking 100-seed weight and seed size as representatives.The result showed that, compared with the wild type Golden Hook, mutant lines of Golden Hook displayed a large phenotypic variations in 100-seed weight, seed length, and seed width, with significant differences between selected wild type and line 434 (large seed) or line 601 (small seed).Also, among 3 500 plants in M₃ lines, compared with the wild type Golden Hook, 607 lines varied significantly in flowering and maturing stages, leaf type, plant type, fertility and seed color; 5.5% mutations were in agreement with median 3:1 segregation ratio, indicating those mutations were generally controlled by single gene.Moreover, some phenotypic mutations were confirmed in M₄ generation.Therefore, the obtained genetic mutants could be directly used in common bean breeding, and provided good materials for cloning the casual genes and thereafter studying gene function as well.