Membranes can be applied to deploy high-capacity, lightweight and large structures in space, such as solar sails, occulters, and sunshields. However, it is difficult to predict the shape of the membranes under low tension in orbit, mainly because gravity deflects the membrane on the ground experiments. We propose a ground-based experimental method to simulate the shape of the membrane in weightless conditions by placing the membrane in an aqueous solution. We developed a small experimental system and measured the shape of the curved membrane that floated in a sugar solution. The effectiveness of the experimental method was evaluated by comparing the experimental results with the results of geometrically nonlinear finite element analysis. In addition, these results were compared with the results of the suspended membrane without gravity compensation.