It is aimed to explore the effects of bud dormancy states on the survival of mulberry germplasm resources during cryopreservation, and to provide scientific basis and technical support for clarifying the suitable dormancy states for cryopreservation of dormant buds. In this study, one-year-old branches of 'Hu mulberry' were sampled on December 8th, 18th, 28th, 2023, and January 7th, 2024, during the winter season. The budding rates, first bud germination times, carbohydrates, osmotic regulating substances and endogenous hormones of the dormant buds were measured. In addition, their survival rates of cryopreservation and recovery were analyzed. Results showed that two dormancy stages of endodormancy to ecodormancy transformation and release of endodormancy into ecodormancy, as well as three dormancy depths of deep dormancy (6 days after entering dormancy), moderate dormancy (16-26 days after entering dormancy) and shallow dormancy (36 days after entering dormancy) were obtained, based on the budding rates and the germination times of the first bud. After cryopreservation of mulberry dormant buds and recovery by tissue culture, the survival rate was up to 90%. With the release of endodormancy for dormant buds sampled, the survival rates after cryoprservation decreased, and the lowest survival rates were obtained when the dormant buds were sampled in the shallow dormancy state (36 days after entering dormancy). During the process of endodormancy of 'Hu mulberry', the content of soluble sugar increased first and then decreased, and reached the maximum at moderate dormancy (26 days after entering dormancy), and then decreased. The starch and soluble sugar contents showed the opposite trends. Soluble protein and proline increased with the release of endodormancy. The contents of four endogenous hormones such as abscisic acid (ABA) during the deep dormancy state (6 days after entering dormancy) were significantly higher than other states. In conclusion, the dormant buds with deep dormancy and moderate dormancy in December (within 26 days after entering dormancy) were selected as the suitable materials for cryopreservation of mulberry germplasm resources.