With the exploration of deep-sea resources increasing gradually, drilling is facing new difficulties. The drill string compensation system is applied to stabilize the floating drilling platform or drilling ship. The system can keep the drill string in a relative static position and protect it from jolting caused by wind and waves, thus allowing the drill bit in constant contact with the hole-bottom, and the bit pressure basically constant. It plays a role in protecting drilling tools and improving drilling efficiency. This paper introduces the advances of the compensation systems, as well as the structure, principle, advantages and disadvantages of various systems. Field cases and data are presented to demonstrate the benefits of the compensation system in improving drilling rates and core recovery.