Abstract: Experiments have shown that Carboxylesterase activity of the rice water weevil, Lissorbqptrus oryzqphilus Kusche1 varied with the rice varietyes.In the 4 rice varieties tested, the esterase activity of rice water weevil feeding on Liaojing454 was the highest, as revealed in the hydrolysis tests with α-NA. It was 4.65 times that of the ice water weevil feeding on T03. The esterase activity of rice water weevil feeding on Liaojing294 was the highest as thown in the hydrolysis tests with β-NA , 4.48 times that of the rice water weevil feeding on T03