Abstract: In order to investigate the effects of different doses of ⁶⁰Co-γ radiation on seed germination and seedling growth of Cunninghamia lanceolata, the seeds collected from the third generation Cunninghamia lanceolata seed orchard were taken as materials to test the effects of different doses of gamma irradiation treatments on the seed germination rate, germination time, seedling emergence rate and the mutagenic seedling growth of Cunninghamia lanceolata. The results showed that: 20 Gy radiation obviously accelerated the germination but the germination rate gradually decreased with the increase of the dose put into application and 80 Gy was a lethal dose; with the dose increase, the germination time gradually extended while the seedling emergence rate gradually decreased when the irradiation dose was between 20 Gy and 60 Gy. Different gamma irradiation doses also had an effect on the height, ground diameter and branch number of the mutated plants, with the increase of irradiation dose, the plants tended to be dwarfed and the ground diameter decreased, while the number of branches first increased and then decreased; in particular, the 40 Gy irradiation dose could significantly accelerate branching. It can be preliminarily ascertained that, according to the irradiation doses, the germination rate and the seedling emergence rate, the half lethal dose of gamma-ray radiation on Cunninghamia lanceolata seeds is between 40 Gy and 60 Gy.