In order to obtain the optimal expression host of MtGH6, we used plasmid pET21a-MtGH6,pBES-MTGH6 and pPICZαA-MtGH6 to express the MtGH6 by use of EScherichia coli BL21、Bacillus subtilis RIK1285 and Pichia pastoris GS115. The growth status, enzyme production, purification efficiency and enzyme activity of the three host bacteria expressing MtGH6 were compared and analyzed. The results showed that the OD value of Escherichia coli BL21 and Bacillus subtilis RIK1285 remained at 1.5 after stable growth, while that of Pichia pastoris GS115 remained at 2.0 after stable growth. MtGH6 produced by Pichia pastoris GS115 was 77 mg/L, and the purification recovery was 15.40%. The enzyme production and purification recovery were higher than those produced by Escherichia coli BL21 and Bacillus subtilis RIK1285. The enzyme activity of MtGH6 expressed by Pichia pastoris GS115 was 15.60 U/mg, and the activity of MtGH6 expressed by Escherichia coli BL21 and Bacillus subtilis RIK1285 was 7.45 U/mg and 10.06 U/mg, respectively, indicating that Pichia Pastoris GS115 was the optimal host for MtGH6 expression. The enzyme properties of MtGH6 secreted by Pichia Pastoris GS115 were studied. The results showed that the optimum pH and temperature of this enzyme were 8.0 and 60 ℃, and the addition of 0.5 mmol/L Mn2+ could increase its activity, indicating that MTGH6 had a good application prospect in the production of biofuels.