Abstract: Cupressus chengiana and Cupressus gigantea belong to the national key protected plants and are the main economic and ecological multi-purpose afforestation species in Hengduan Mountain areas of China. It is of great significance to study the seed characteristics, germination law and the effects of environmental conditions on seed germination in ecological restoration, biodiversity protection and resource protection. In this study, C. chengiana and C. gigantea, which are closely related, were selected as the research objects for seed germination test. The results were as follows: (1) The transverse diameter, longitudinal diameter, thickness and 1000-grain weight of C. chengiana seeds were higher than those of C. gigantea seeds, and the seed morphology was significantly different. (2) There was significant difference in seed soluble protein content between C. chengiana and C. gigantea. The seed soluble protein content of C. gigantea (0.0687±0.0204 mg·g⁻¹) was higher than that of C. chengiana (0.0459±0.0100 mg·g⁻¹). (3) The content of soluble protein was negatively correlated with soluble sugar, positively correlated with crude fat, and the content of soluble sugar was negatively correlated with crude fat. (4) The optimum temperature for seed germination of C. chengiana and C. gigantea was about 25℃, and there was no significant difference in germination rate, while the germination rate of C. gigantea was slightly higher. Low temperature (−10℃) treatment was beneficial to seed germination of C. chengiana.