【Objective】To investigate the effects of pH and temperature on cellulose enzyme activities of Pomacea canaliculata Lamarck and Cipangopaludina chinensis Gray. 【Method】 The enzymatic analysis method (Carboxymethyl cellulose method) was used to research the influences of different reaction temperatures and pH values on cellulose enzyme activities in liver and stomach of P.canaliculata and C.chinensis. 【Result and conclusion】 The cellulose enzyme activities in liver and stomach of P.canaliculata were significantly higher than those of C.chinensis under different pH and temperature. The cellulose enzyme activities in liver and stomach of P.canaliculata at different pH values(3.6-7.2) were 1.51-3.14 and 1.30 -1.90 times higher than those of C.chinensis, respectively. At different temperatures (30-60 ℃), the cellulose enzyme activities were 1.16-1.56 and 1.32-1.77 times higher than those of C.chinensis, respectively. At the settled pH(3.6-7.2) and temperature (30-60 ℃) conditions, the curves of cellulase activities were all rising followed by reducing. At different temperatures, the variation ranges of cellulase activities in liver and stomach of P.canaliculata were wider than those of C.chinensis, while there was no significant differcence between P.canaliculata and C.chinensis at different pH values. The optimum pH range for cellulose enzyme activities in liver and stomach of P.canaliculata were 5.4-6.6 and 4.8-6.6, respectively; the optimum temperature range was from 40 ℃ to 55 ℃. Meanwhile, The optimum pH ranges for cellulose enzyme activities in liver and stomach of C.chinensis were 5.4-6.0 and 4.8-6.6, respectively; the optimum temperature ranged from 40 ℃ to 50 ℃. P.canaliculata has a better digestive ability and is more adaptive to the environment which may attribute to the easier invasion mechanism of P.canaliculata.