An investigation was conducted in order to understand the cold tolerance of 400 accessions of sugarcane germplasm maintained in Sugarcane Research Center, Chinese Academy of Agricultural Sciences/ Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences at Nanning, China. Different cold tolerant groups were clustered based on internode and internode growing point injury index by system clustering method during the extreme low temperature disaster in early 2008. The low temperature in early 2008 was a rainy frost type. The cold tolerance of 400 accessions of sugarcane germplasm could be divided into 5 groups, that is, strongest cold tolerance group, strong cold tolerance group, average cold tolerance group, poor cold tolerance group and poorest cold tolerance group, which include 226 (56.50%), 103 (26.75%), 53 (13.25%), 7 (1.75%) and 7 (1.75%) accessions of sugarcane germplasm, respectively. The Cold Tolerance Index (CTI) of sugarcane could be calculated as: CTI = 0.3× internode injury index+0.7× internode growing point injury index. The internode growing point was more sensitive than internode tissue for low temperature injury, and CTI could be used to evaluate the cold tolerance of sugarcane germplasm under rainy frost.