Abstract: Two winter wheat cultivars with different drought tolerance were performed to investigate the relationship between the grain filling and the accumulation and remobilization of water soluble carbohydrates (WSC) in flag leaves and different internodes of main stems during the grain filling in the drought stress (DS) and well watered (WW) conditions. Such tested traits as WSC contents,WSC remobilization rates and WSC contribution rates of different organs,grain weight and grain-filling rate were more significantly affected by the water condition,growth stage and/or organ,whereas different tested traits showed significant specificity in response to above-mentioned factors. The variation trend in WSC contents of different organs was of a rise first and then fall during the grain filling. The maximum WSC content of drought-tolerant cultivar Longjian 19 occurred on 18 DAA (days after anthesis) under both the DS and the WW,while did on 12 DAA in water-sensitive cultivar Q9086 in the DS. The DS might substantially increase WSC accumulation in different organs and improve WSC contribution rates to grain weight by remobilizing WSC built up in different organs during the pre-anthesis. The profit was more conducted in peduncle and penultimate internodes of Longjian 19. In this case,WSC contents,in turn,were up to 196.83 and 242.35 mg/g DW,WSC remobilization rates reached to 66.15% and 63.21%,and WSC contribution rates were up to a maximum of 12.48% and 8.67%,respectively. Although the DS shortened the course of grain filling,Longjian 19 still performed higher grain-filling rate and greater grain weight of main spikes. Positive correlations were found not only between WSC contents of different organs and grain-filling rates of main spikes,but also between WSC remobilization rates and its contribution rates. Furthermore,these correlations were significantly higher under the DS than the WW condition. It indicated that drought stress could enhance the accumulation and remobilization of WSC of different organs in wheat,and more buildup of WSC in peduncle and penultimate internodes might play an important role in compensating grain filling under the DS.