The present paper deals with the monthly variations in physico-chemical characteristics and planktonic diversity of Barwala Link Canal which link the Bhakra Main Canal with Sirsa Branch of Western Yamuna Canal in Narwana Region, Haryana. Surface water samples were collected on monthly basis and analyzed for physico-chemical parameters (water temperature, total dissolved solids, electrical conductivity, turbidity, pH, dissolved oxygen, free CO₂, alkalinity, hardness, chlorides, biochemical oxygen demand, o-phosphate, nitrate and ammonia). An attempt was also made to assess the biological parameters including population density, their abundance and species diversity index of plankton life which were used as a measure of water quality. Phytoplankton was abundant as compared to Zooplankton. A total of 14 taxa of phytoplankton were recorded of which 9 taxa of Chlorophyceae and 5 taxa of Bacillariophyceae. 8 taxa of zooplankton were recorded of which 4 taxa of protozoa, 3 taxa of rotifera and one taxa of insecta. Shannon diversity index of phytoplankton ranges from 2.47 to 3.29 and Zooplankton ranges from 2.60 to 2.99. It is revealed that the quality of canal water is good throughout study period as estimated by the weighted arithmetic index method.