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 region of our country. The seed characteristics, germination laws and effects of environmental conditions on seed germination are studied. Biodiversity protection and resource protection are of great significance. In this study, Cupressus chengiana and Cupressus gigantea were selected as the research objects for seed germination test. The results showed as follows: 1) The transverse diameter, longitudinal diameter, thickness and 1000-grain weight of Cupressus chengiana seeds were higher than those of Cupressus gigantea seeds, and the seed morphology was significantly different. 2) There was significant difference in seed soluble protein content between Cupressus chengiana and Cupressus gigantea. Cupressus gigantea seed soluble protein content (0.0687±0.0204 mg·g⁻¹) was higher than Cupressus chengiana (0.0459±0.0100 mg·g⁻¹). 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. 3) The optimum temperature for seed germination was about 25℃, and there was no significant difference in germination rate, while the germination rate was slightly higher. Low temperature (−10℃) treatment was beneficial to seed germination of Cupressus chengiana.