Abstract: In order to explore the optimal pH value and temperature of the enzyme activity in the intestinal tract of Cyrtotrachelus buqueti larvae, different cellulase activities in different segments of intestinal tract (foregut, midgut, hindgut) were carried out under the interactions of different pH values and different temperatures. The optimum temperature range of exo-β-1,4-glucosidase activity was 50−60 °C (0.03 ± 0.005 μmol·min⁻¹·mg⁻¹), and the optimum pH was 5−6 (0.02 ± 0.005 μmol·min⁻¹·mg⁻¹). The optimum temperature range of endo-β-1,4-glucosidase activity was 50−60 °C (0.23 ± 0.005μmol·min⁻¹·mg⁻¹), and the optimum pH was 4−7 (0.02 ± 0.005 μmol·min⁻¹·mg⁻¹). The optimum temperature range of β-glucanase activity was 40−60 °C (0.02 ± 0.005 mol⁻¹·mg⁻¹), and the optimum pH was 4−7 (0.02 ± 0.05 μmol·min⁻¹·mg⁻¹). Temperature and pH had significant effects on cellulase activity in the insect intestinal tract.