Abstract: The study aims to explore the effect of carbon monoxide (CO) on the growth of Phellinus linteus mycelium and the accumulation of triterpene. As the donor of carbon monoxide, hemin was added in the Phellinus mycelium culture, then, different methods such as pH instrument, TDS, colorimetry, HPLC were used to analyze the pH value, conductivity, H2O2, O2- , antioxidant enzyme activity and content of triterpene. The results showed that: the change of pH value was not obvious under the influence of CO; only the treatment with 30 μmol/L hemin for 1-8 days had the best inducing effect on the conductivity and accumulation of H2O2, HPLC, O2-, which declined in other concentrations; conversely, antioxidant enzyme activities were reduced in the 30 μmol/L CO treatment, and were increased in other concentrations; triterpene and betulin were decreased only in 30 μmol/L CO treatment, and were increased in other concentrations; the triterpene had the largest growth rate on the fourth day with 10 μmol/L CO, increased by 29.63% compared with CK in the same period; and the betulin had the largest growth rate on the first day with 20 μmol/L CO, increased by 30.96% compared with CK in the same period. Obviously, low concentration of CO treatment has no damage to Phellinus mycelium, and improves its bio- accumulation, but the biological effect still needs to be verified by many materials.