Abstract:Soil macropore is the main channel for preferential transport of soil moisture, air,chemical substances and pollutants, so the studies on its formation mechanism are of great importance. In the past, the quantification of macropore was limited to the traditional methods. But nowadays, quantitative analysis of three-dimensional morphological characteristics of soil macropore and its influencing factors are the research focus. In this paper, CT scanning and image processing techniques were used to quantify the 3-D characteristic parameters of macropore, and the basic physical and chemical properties of soil and root length density were also determined. The correlations between soil physicochemical properties, soil roots and the 3-D characteristics of soil macropore were analyzed. The results showed that there was no correlation between soil density, soil sand contents and characteristic parameters of macropore; soil organic matter contents and root length density were significantly positively correlated with volume density, surface area density and number density of macropore, and significantly negatively correlated with mean tortuosity of macropore. Soil organic matter and roots had a positive impact on the 3-D characteristics of soil macropore, the more roots and organic matter contents, the more macropore contents, and the worse bending degree of macropore. In the future, the effects of root system and organic matter should not be neglected in the studies of forest tending and management, soil water movement mechanism and groundwater pollution assessment.