Thermocapillary convection is a common flow in space. Experiments regarding thermocapillary convection were previously carried out in a large-scale liquid bridge with a diameter of 20 mm on the Tiangong-2 space station, and the transition process to chaos was systematically studied. Under microgravity conditions, gravity is greatly weakened, and the transition process of the flow is very slow. This allows for the opportunity to study the bifurcation process in detail. It has been found that there are abundant nonlinear physical phenomena associated with the changing geometric parameters in thermocapillary convection systems. The transition mechanisms interact with each other, leading to various transition routes. The phase space trajectories, the Lyapunov exponents, and correlation dimensions are calculated to distinguish the chaotic state under a variety of conditions. Through the chaotic dynamics analysis, the chaotic characteristics of the entire transition process are quantitatively discussed.