Taking rotary drilling rig automatic positioning control system as the research object,the rotary drilling rig automatic positioning system and the principle of S curve were analyzed.According to adjustment method of S curve,the rotary drilling rig automatic positioning control algorithm based on S curve was proposed.And the algorithms were classified analysis and design.In order to verify the feasibility and reliability of S curve acceleration and deceleration algorithm,it was tested in highspeed motion controller of the rotary drilling rig.The test results show that this method can satisfy the control of rotary drilling rig automatic positioning,and has the advantages of rotary drilling rig smooth operation,high control precision.