In order to improve the decay resistance of wood as the renewable natural material of biological origin, an organic preservative, 3-iodo-2-propynyl butyl carbamate (IPBC), was penetrated into wood matrix by supercritical CO2 as a carrier solvent. And the effectiveness of penetrating IPBC into wood matrix through SC-CO2 was also examined in terms of preservative distribution, leachability resistance of preservative as well as decay resistance of wood. The results indicate that the optimum penetration craft under the adopted conditions was pressure: 19MPa, temperature: 35°C, pressure time: 2.5h and time for releasing pressure: 20min. And under the optimum condition, the mechanical properties of SC-CO2 treated wood were not significantly affected. SEM-EDX analysis indicate that IPBC mainly distributed in wood matrix due to the higher penetration of supercritical CO2 as a carrier solvent, and its leachability was remarkably reduced after such penetration. The decay resistance of SC-CO2 treated wood against fungi attack was improved 90.96% over untreated wood, indicating effective decay resistance of wood after preservative penetration with SC-CO2.