Limiting device, three-dimensional storage system and goods access method

The invention discloses a limiting device. The limiting device comprises a limiting mechanism and a unlocking mechanism. The limiting mechanism is arranged on a goods shelf. The limiting mechanism comprises a swing frame, a swing block, a sliding seat, a pushing rod and a connecting rod. The swing frame and the sliding seat are both fixedly arranged on the goods shelf. A hinged end of the swing block is hinged with the swing frame. The swing block rotates in a vertical plane. When the swing block is in a first limiting position, goods on the shelf are limited. When the swing block is in a first unlocking position, the goods on the shelf are unlocked. The pushing rod is slidably connected with the sliding seat. A driving end of the pushing rod is movably connected with the middle of the swing block through the connecting rod. When the push rod is in a second limiting position, the swing block is in the first limiting position. When the push rod is in a second unlocking position, the swing block is in the secon