In the present investigation where the ecology of aquatic insects in Joysagar Tank was conducted for a period of six months, it was observed that the insects recorded an increase tendency of abundance in the spring seasons. The results revealed that the aquatic insects belonged to five major orders of Hemiptera, Ephimeroptera, Odonata, Coleoptera and Diptera. Hemiptera was found to be the most dominant group among all the orders.Seasonal variation of insects might have been influenced by temperature and rainfall.