From five termites guts samples collected in different places in Ha Noi and Vinh, 11 isolates which formed halo on agar plates with CMC were isolated. Among them strain G4 possessed the highest CMCase activity. Based on morphology and 16S rRNA gene sequences analysis, G4 was identified as Bacillus subtilis G4. The results from cultivation study revealed that M3 medium containing rice bran 1 %, soy flour 1 %, casein 1 % and 1 % NaCl was the best medium for cellulase production of B. subtilis G4. At optimal conditions for G4 which were inoculums ratio 1 %, cultivation temperature 37ºC, cultivation time 72 hours, shaking speed 150 rpm and initial pH medium 7, CMCase and FPase activity reached 3.36 U/ml and 0.35 U/ml, respectively.