The effect of each component and their ratios of cyclohexane/ water/ Tween-80/ n-butanol microemulsion on its formation were studied, and the system’s physicochemical properties have also been characterized by conductivity, surface tension and dynamic light scattering (DLS) measurements. The results showed that the microemulsion forming area was largest by using Tween-80 as the surfactant, n-butanol as co-surfactant, and cyclohexane as oil. The conductivities of the system represented regularity along with water content increasing, and the three types of microemulsions (water-in-oil, bicontinuous and oil-in-water) could be distinguished. Different types of microemulsions had very low surface tension (about 24.6 mN/m) and small practical size (less than 100 nm), increasing along with the water content of the system. Furthermore, the osmosis of the microemulsion for wood was investigated by liquid absorption method. Compared with other solvents, microemulsions showed greater penetration ability for wood. Especially for the bicontinuous microemulsion, its osmosis for pine and eucalyptus at 10min attained 70% and 50%, respectively.