In deep-sea drilling， the drilling process without a riser is not limited by the length of the riser， and can carry out drilling operations within all water depths. However， as the water depth increases， the difficulty of drilling tools re-entering the borehole is extremely high， and the drilling re-entry system is particularly important for drilling without a riser. The working conditions of deep-sea drilling are very complex， and due to various factors such as ocean waves and currents， the drill string is approximately a flexible rod. Without the use of ROV， the conventional drill string re-entering operation takes a long time and has a low success rate. Even if the drill string is moved by the upper moving ship due to sea conditions， it is difficult to achieve. Therefore， studying the deviation control technology of the drilling re-entry system is of great benefit for deep-sea drilling. By analyzing the posture and efficiency of the drill string re-entering the borehole in a free state， a drilling re-entry system with a driving device is used to balance the hydrodynamic effect at the bottom of the drill string， effectively ensuring the stability of the bottom drilling tool during re-entering the borehole， minimizing the re-entery drilling time， and reducing the cost of the deep-sea non riser drilling process.