Abstract: The systemic experiment has been done to measure the onset instability of nonpropagating hydrodynamic solitons for various depths,breadths,and the ratio of the mixture solution of the glycerin and water.The experiment shows that increasing the depth and breadth,and decreasing the ratio of the mixture mainly lead to the decreasing of the onset exciting acceleration.The experimental results are qualitatively consistent with the linear stability theory in which the horizontal wave number has been quantized due to the finite boundary of the small-aspect-ratio container.