The invention discloses an automatic line-grasping control method of a deicing robot in a high-voltage transmission line. An enhanced learning system is established by setting a state set, an action set, a Q table and a reward function. The method comprises the following steps of: selecting an action a to act on the environment by the system; after the action is accepted, transferring the environment to next state s'; meanwhile, giving out an evaluation signal r; if r meets certain conditions, stopping controlling, and otherwise deciding next action a' by the enhanced learning system according to the evaluation signal and the state s' through a behavior selection strategy; and entering next iteration after updating the Q table. The method overcomes the influence brought by the model errorof the robot, inaccurate posture at the tail end of robot arms, complicated environment and the like, and can be used for adjusting the posture at the tail end of the arm on line in real time for realizing the quick and accurate line grasping of the arm without human remote control, thereby achieving the aim of the automatic line-grasping control.