To investigate the differences of digestive ability between the alien golden apple snails (Pomacea canaliculata (Lamarck was, 1828)) and local field snails (Cipangopaludina chinensis (Gray, 1832)), and hence to explore the successful invasion mechanism of golden apple snails, we assayed the following digestive enzyme activities: cellulose enzyme activity (carboxymethyl cellulose method), amylase activity (3, 5-2 nitro salicylic acid method) and lipase activity (titration), with the samples taken from liver and stomach of the apple snails and local snails at different ages (from 1 to 4) using local snails as control. The results demonstrated that: 1) The digestive enzyme activities in stomach and liver of golden apple snails of the same age group were significantly higher than those of the local field snails. Among them, the cellulase activity of golden apple snails was 1.00 to 2.11 times and 1.66 to 2.84 times higher than those of local field snails, respectiviely; Amylase activity of golden apple snails was 1.53 to 3.47 times and 1.47 to 1.80 times higher, respectively; Lipase activity was 2.07 to 4.73 times and 6.13 to 9.93 times higher, respectively. 2) The variation amplitudes of different digestive enzyme activities in the stomach and liver of golden apple snails (51.2%-131.2%) were significantly higher than those of local field snails (23.3%-47.1%) during growth and development. 3) There were synergistic effects between digestive enzymes of golden apple snails. For example, the amylase activity of golden apple snails were significant positively correlated with the activity of lipase (r=0.736^{* *} in the stomach, r=0.867^{* *} in the liver). In addition, the amylase activity in the stomach was significant positively correlated with cellulose enzyme activity (r=0.696^*). Accordingly, there was also a significant positive correlation between amylase and lipase activities in the stomach of local field snails (r=0.706^*), while the cellulase and lipase activities in the liver were significant negatively correlatied (r=-0.593^*). 4) Golden apple snails have strong abilities to digest cellulose and starch, and could digest fatty substances as well. Local field snails could digest cellulose and starch, but the digestion ability for fat was very weak. The cellulase and amylase activities of golden apple snails were 2.42 and 1.88 times higher than those of local field snails, respectively, and the lipase activity even reached 5.66 times. In conclusion, golden apple snails have much higher digestive enzyme activities, and there are positive synergies between various digestive enzymes, which lead to its big appetite and omnivorous predation. This could be one of the important factors that result in the golden apple snails growing very fast and invading successfully.