Abstract: The single-bucket and multi-compartment structure has been applied in breakwater engineering. However when it used as a vertical quay wall structure, backfilling at the land side is required, and its safety and reliability have not been verified. The internal forces of the bucket-based structure are measured by the in-situ tests, and those of the lower barrel wall, the compartment, the cover plate and the upper barrel wall are obtained. The variation curves of the vital part of concrete strain with time and reinforcement stress with time are plotted under the backfill loads. The development laws of internal force of each part of bucket structure are found, and the stress state of bucket structure at the land side under the backfilling condition is understood. The test results show that the structure has good stability in the backfilling process, and it may provide data support for further optimization of the structure.