The utility model provides a transmission line unmanned aerial vehicle patrols and examines flight control system and automatic obstacle -avoiding device, automatic obstacle -avoiding device includes that interconnect's environment perceptual arrangement hinders the master control terminal with keeping away, environment perceptual arrangement includes laser radar, ultrasonic radar and vision sensor, keep away the ARM chip that barrier master control terminal includes interconnect, DSP chip and FPGA chip, environment perceptual arrangement adopts multiple type sensor accuracy to acquire unmanned aerial vehicle barrier positional information data on every side, keep away barrier master control terminal and adopt ARM+DSP+FPGA's chip framework, and with being loaded with SLAM software, carry out the SLAM operation, distance between the barrier around real -time calculation unmanned aerial vehicle self position and the unmanned aerial vehicle, when around unmanned aerial vehicle self position and the unmanned aerial vehicle between the barrier distance be less than when predetermineeing safe distance, update the planning of unmanned aerial vehicle flight path, realize that transmission line unmanned aerial vehicle patrols and examines the automatic barrier of keeping away.