The ability to obtain sufficient nutrients and energy from the environment determines the survival and reproduction of animals. To clarify the digestive strategies of changing nutrient contents for sympatric rodents with different body sizes, the Mus caroli and Rattus losea were fed with three diets with varied nutrient content. On the 10th and 20th day, the food intake, fecal output, net food intake and apparent digestibility were determined using the food balance method. The results showed that there was no significant change in body weight between the three food groups of M. caroli and R. losea during experiments, indicating that they were able to adapt to changes in food quality. In M. caroli, the daily intake of high-protein group on the 10th day was no different from that of the normal group, but significantly higher than the high starch group; the fecal output of the high protein group was significantly higher than that of the high starch group and the normal group. The apparent digestibility of the high starch group and the normal group was significantly higher than that of the high protein group. On the 20th day, there was no difference in daily food intake among the three groups of animals; the daily fecal output in the high protein group was higher than that in the high starch group and the normal group. The Rattus losea showed only 10 days when the high starch group and the normal group had higher apparent digestibility than the high protein group. This study revealed that M. caroli and R. losea can be adapted to changes in the nutrient composition of the food through different feeding and digestion strategies, although the difference in body size are large between the two rodents.