The aim of the study was to get better insight of some biochemical parameters reflecting hepatic and renal functions in the blood plasma of Red-bellied Squirrel (Callosciurus erythraeus). During the course of a one-year period 76 male and 85 female adult squirrels were captured from February to December 2015, respectively from Yingjing County, Sichuan Province. These indices were statistically analyzed for differences between gender, season and pregnancy by two-way ANCOVA or one-way ANCOVA. No significant sex difference was found for serum hepatic and renal function markers in red-bellied squirrel (Fig. 1﹣3). No significant difference but higher serum concentrations of albumin (Fig. 1b), cholinesterase (Fig. 1c) and creatinine (Fig. 3a) were found in the spring compared to the other seasons. The serum concentrations of total protein (Fig. 1d), globulin (Fig. 1e) and uric acid (Fig. 3c) were significantly higher in the spring, while total bilirubin (Fig. 2a), direct bilirubin (Fig. 2b), indirect bilirubin (Fig. 2c) and blood urea nitrogen (Fig. 3b) were obviously lower. Alanine aminotransferase (Fig. 2d), pre-albumin (Fig. 1f), aspartic transaminase (Fig. 2d) and γ-glutamine transferase (Fig. 2f) concentrations were significantly higher in the spring compared to other seasons and markedly decreased in the summer, then reached nadir in the winter. Serum concentrations of blood urea nitrogen (Fig. 4a), creatinine (Fig. 4b) and uric acid (Fig. 4d) were significantly lower in pregnant squirrels compared to non-pregnant individuals, while the concentration of cholinesterase (Fig. 4a) was significantly higher in pregnant squirrels. These results indicated seasonal differences in blood biochemical parameters in red-bellied squirrels. Most of the studied parameters were the lowest or highest in the spring, but less impacted by pregnancy. This might be related to reproductive status of male and female squirrels and the ability of physiological adaptation to the diversities of environments.