Plant root exudate is a naturally occurring resource, constituting various chemical compounds which alter the micro-environment around the root and plays a significant role in plant-microbe interaction. The interaction may be positive or nagetive. Root exudates are often divided into two classes of compounds. Low-molecular weight compounds such as amino acids, organic acids, sugars, phenolics, and other secondary metabolites account for much of the diversity of root exudates, whereas high molecular weight exudates, such as mucilage (polysaccharides) and proteins, are less diverse but often compose a larger proportion of the root exudates by mass. The present paper tries to understand the nature of chemical composition of root exudate and type of interaction with microbe