In this paper, an electrostatic-immune AC-based electrical capacitance tomography (ECT) is developed to visualize the gas-solid flow inside the circulating turbulent fluidized bed (C-TFB) reactor. A fractal gas distributor based on fractal self-similarity theory is used to improve the particle distribution by re-distributing the intake gas. Experiments are carried out on a cold model of lab-scale C-TFB to investigate the effect of the fractal gas distributor using the electrostatic-immune ECT. Experimental results show that the particle concentrations with the fractal gas distributor are higher than those without the fractal gas distributor under identical operation conditions, indicating that the fractal gas distributor is favorable to enhance the upward movement of particles inside the C-TFB reactor. Moreover, the radial particle distribution with the fractal gas distributor is more even at a certain area of C-TFB, indicating that the fractal gas distributor can improve the radial uniformity of C-TFB within its active region.