The self-written dynamic positioning time-domain simulation program is adopted. Taken a drilling ship as an example, the internal solitary wave load is modeled and time-domain simulation is performed. The internal solitary wave is incorporated into the environmental load, and the time-domain simulation results of the dynamic positioning of the ship under internal solitary waves are obtained. It is obtained that the operating window interval of the ship is . The dynamic positioning performance of the ship is evaluated based on the motion response of the ship and the power consumption of the propeller, and the recommendations for marine operations when the ship encounters internal solitary waves are put forward.