A rock true-triaxial testing system based on computerized tomography (CT) scanning aims to solve problems in the prior art, that is, the rigidity of the frame in the testing system is insufficient; high-pressure lines, wires, and signal lines are entangled when rotating; and the reaction frame and loading actuators obstruct the ray. The rock true-triaxial testing system includes a true-triaxial loading system and a high-energy accelerator-based CT scanning system, where the high-energy accelerator-based CT scanning system is located inside the true-triaxial loading system, and the high-energy accelerator-based CT scanning system is configured to image an internal structure of a cubic rock sample and continuously apply a stress to the cubic rock sample through a plurality of piston extension rods in the true-triaxial loading system. The rock true-triaxial testing system reduces radiation attenuation, and ensures imaging quality and a stable and smooth loading process.