Abstract: In order to explore the microscopic mechanisms associated with the macroscopic mechanical properties of soil, it is necessary to investigate the microscopic mechanical behaviors of soil. Based on the conventional triaxial apparatus, a miniature triaxial apparatus suitable for industrial CT system scanning is developed, which includes loading device and acquisition control system. The main features are as follows. The loading device can be put into CT equipment for rotary scanning because of small size and light weight. The specimen can be scanned clearly to obtain the microstructure and mechanical information of soil under triaxial stress. The reliable test data can be obtained. The miniature triaxial apparatus has strong compatibility, which does not affect the function of CT and does not also refit CT. It also has the advantage of convenient operation and low price. The contrast tests for the dry Toyoura sand samples are carried out by the miniature triaxial apparatus and conventional triaxial apparatus. The results show the stress-strain relationship and angle of internal friction obtained from miniature triaxial apparatus are in agreement with that obtained from the conventional triaxial apparatus. There is little difference on angles of internal friction obtained by two apparatus. Thus the reliability of the miniature triaxial apparatus is verified.