【Objective】Soil structure is the key to understanding physical, chemical, and biological processes that play a vital role in biodiversity and agricultural productivity. However, due to the mutual influence and simultaneous progress of these process, soil structure evolution has become irregular, unstable, and highly complex. With the development of computer technology on CT scanning images, different scaling and descriptive statistical analysis allow for a better study of soil pore structure or architecture. 【Method】In this study, the saline/sodic soil in the coastal reclamation area of Jiangsu Province was taken as the object of investigation. Based on multifractal and relative entropy theory, combined with Micro-CT technology, the scaling features of the pore structure of biochar-amended saline soil were revealed. 【Result】In this study, the surface soils (0-20 cm) were amended by thoroughly mixing with biochar at three application rates (0%, 2% and 5% by mass of soil) in a completely randomized design. This experiment lasted for four years from 2017 to 2020. To reveal the scaling characteristics of CT pores, two methods were applied: multifractal analysis (MFA) and relative entropy (E). The results showed that different theoretical methods should be used to analyze the complex scaling behavior of soil pores. The multifractal method was suitable for grey images, while the relative entropy method was suitable for binary images. The pore complexity of all treatments increased from one year to the next. Also, the addition of biochar accelerated the developments of soil pore structure and induced a faster rate of increase in pore complexity. Among different biochar treatments, the pore complexity of 2% biochar treatment was the highest (∆α=0.061，Range∆E=0.436) and the improvement effect was the best. The addition of high biochar (5% biochar treatment) reduced the pore complexity (∆α=0.045，Range∆E=0.531), reducing the improvement effect of biochar. 【Conclusion】This study can provide a theoretical basis for the use of biochar to improve pore structure from a microscopic point of view.