In this paper, the evolution of thermocapillary convection in melt of half-floating zone liquid bridge under the condition of zero gravity was studied by means of numerical simulation. Under the condition that the height L of the liquid bridge and the temperature difference ΔT remain unchanged, the aspect ratio (Ar=L/R) of the liquid bridge can be changed by changing the radius R of the liquid bridge. The convection in the liquid bridge exhibits various flow characteristics with the change of the aspect ratio Ar. Thermocapillary convection is in a three-dimensional steady state when Ar=0.5. The flow field and temperature field change from the steady state mode to the unsteady periodic multi-frequency oscillation mode satisfying the frequency doubling relationship (fn=nf1) when Ar=1. When Ar=1.25, the velocity oscillation frequency of the monitoring point increases, showing a smaller amplitude oscillation mode, and the temperature oscillation disappears.