To analyze the deterioration mechanism of rubber isolation bearings at low temperatures， the low temperature crystallization properties of rubber materials used for isolation bearings in China under no-strain conditions were investigated. Differential scanning calorimetry （DSC） was used to investigate the glass transition temperature and isothermal crystallization melting of natural vulcanized rubber used for the production of isolation bearings by two typical enterprises in China. The results show that the crystallinity of the isolation bearing increases with the extension of the holding time at low temperatures without strain. Additionally， the crystallization properties of different vulcanized natural rubbers are different due to various factors such as origin， growing environment， and vulcanization process. Only when the ambient temperature is below -60 ℃ the rubber isolation bearings produced by the materials used in this study lose their practical engineering value. In the actual service process， the isolation bearing is affected by the dual factors of low temperature and strain. The research results in this paper provide a reference and basis for revealing the deterioration mechanism of the mechanical properties of the isolation bearing at low temperatures and enhance our understanding of the mechanical behavior of the rubber isolation bearing at low temperatures.