The invention discloses a construction method of a cross-shaped pull trough of an open caisson. The construction method comprises the steps that firstly, after height addition of the open caisson is completed, the cross-shaped pull trough is excavated in a compartment of the open caisson with the center of the compartment as the center of the cross shape, the section of the cross-shaped pull trough is in an inverted-parabola shape, the excavation depth in the center position of the cross-shaped pull trough is the largest, the cross-shaped pull trough is excavated till the open caisson sinks, and height addition is conducted again after the open caisson sinks to the specific elevation; and secondly, the first step is conducted repeatedly till the open caisson sinks to the designed elevation. According to the construction method of the cross-shaped pull trough of the open caisson, the structural force of the open caisson in the sinking stage is optimized, the problem that the open caisson is prone to cracking through pulling in a traditional open caisson excavation and sinking method, and the construction method has a good function for solving the problem that the excavated open caisson cannot sink and preventing sudden sinking.