The problem of robot auto-recharging must be solved to make the robot in a continuous task loop.Auto-recharging of security robot is studied and infrared docking technology is introduced which is used for the robot docking.The docking is successful for 45 times in 50 experiments in the case of different distance and 22 times in 30 experiments in the case of different angle.Several experiments are made to prove the feasiblility of the method.