Based on a self-floating underwater bed leveling machine, this paper designs and analyzes the lifting system, an important part of the leveling machine, and proposes a lifting system with simple structure and reliable operation. For the lifting mechanism which is composed of lifting system, the hydraulic ring beam bolt type lifting mechanism, gear and rack type lifting mechanism and hydraulic lifting mechanism are proposed. And cross rotation supporting mechanism and universal ball bearing supporting mechanism are considered for the device supporting. Besides, a wedge lock mechanism and a pawl lock mechanism are proposed for the lock mechanism. Finally, the lifting system is composed of hydraulic lifting mechanism, cross rotating supporting mechanism and pawl locking mechanism. At last, the transient dynamics of the pawl locking mechanism was calculated, and the results show that the maximum stress of the pawl locking mechanism is 152.52MPa that less than the allowable stress, 172.5MPa, which verifies that the strength of the pawl locking mechanism meets the requirements.