The pattern changes of SDS-PAGE protein in sugarcane roots subjected to water stress condition were studied.The sugarcane cultivar ROC22 was used as the plant material and treated with nutrient solution containing 100 g/L polyethylene glycol 6000(PEG 6000) for simulating drought stress.The proteins were isolated from different samples by SDS-PAGE.The results revealed that a new 44.5 ku protein band was appeared stably during 24 h PEG stress,which may be the main regulatory protein responding to water stress.The relative content of 57.1 ku and 29.0 ku protein bands changed actively during 24 h PEG stress,the former increased and the latter decreased markedly at the early PEG stress stage.The relative contents of the 62.7,48.2 and 40.4 ku proteins remained unchanged for a long time at the late PEG stress stage.The most active changes of the protein bands were found at 14 h PEG stress,and a new protein band of 44.5 ku appeared,the 25.5 and 18.9 ku protein bands disappeared while the 81.8,48.2,38.0 and 29.0 ku protein bands declined markedly in roots at the same time. The proteins might play an important role in gene expression and regulation in roots of sugarcane,and its changes could be correlated with the PEG stress.