Abstract: 【Objective】This study aimed to provide theoretical foundation and technical procedures of radiation mutation breeding for Camellia semiserrata and to improve the germplasm resource of this species. 【Method】Different doses of ⁶⁰Co-γ ray irradiation were applied to the dry seed of this species, and the effects on seed germination and seedling growth were investigated.【Result and conclusion】Seed germination rate and seedling survival rate were reduced after irradiation treatment. Extremely significant positive correlation existed between irradiation and seedling mortality in the range of 10-90 Gy dose. The half lethal dose of radiation of the test samples was 47 Gy. The inhibition effect on seedling height and its ground diameter growth was found after different irradiations, and some seedlings produced a few branches. However, no obvious deformity in the seedling morphology is found.