In order to explore the monosaccharide composition and contents in root exudates and plant tissue,four flue-cured tobacco varieties were used as the experimental material.The composition and contents of monosaccharide in rhizosphere,non-rhizosphere soils,root and leaves of each variety were analyzed with high performance capillary electrophoresis in pot experiment.Six monosaccharides analyzed in all of varieties,they were xylose,glucose,galactose,ribose,arabinose,and rhamose.The composition and contents of monosaccharide were different in rhizosphere soils,non-rhizosphere soils,root and leaves.In the same variety,leaves have the highest content,root takes second place,and rhizosphere,non-rhizosphere soils are the least.The correlation analysis show that there was a positive correlation between rhizosphere soils,non-rhizosphere soils,leaves and roots in total contents of xylose,arabinose,glucose,rhamnose and galactose.There was also a significant positive correlation between different monosaccharide for some of them.The results indicated that monosaccharides of root were secreted along with concentration gradient and diffused into rhizosphere.