Molluscs are considered the most diverse and dominant benthic fauna both from lentic and lotic ecosystem. The diversity, seasonal variations and their correlation with the physicochemical parameters of Ranipur dam have been studied. A correlation between Molluscs collected by using unit cover method and water samples collected from three points from reservoir have been attempted. The biotic samples and water samples carried to laboratory for qualitative and quantitative evaluation with respect to Molluscan density and species richness while abiotic components of water have been analyzed over three seasons monsoon, winter and summer. In Ranipur dam eleven species and nine genera of aquatic Molluscs were recorded in Ranipur dam. To find out correlation of Molluscs density with their habitat and physico chemical parameters of water samples were analyzed by using standard methods. The densities of Molluscs were calculated on the basis of the volume of the cover used for the collection of soil samples. From these nine species belongs to class gastropod and two species to class bivalvia. The value thus obtained have been used to find out correlation between water parameters and density and species richness of Molluscs by keeping Molluscs as dependent variables and abiotic factors as independent variables. Maximum density in monsoon and minimum in winter. The positive or negative significant or non-significant correlations of molluscan density and species richness with physicochemical parameters of water that produce cumulative effect are discussed.