In robot-assisted live-line maintenance, bilateral teleoperation is still a popular and effective approach in assisting operators to accomplish hazards tasks. Particularly, teleoperation under overhead power lines attach greater expectation on safe operation and telepresence. In this article, we propose a visual-haptic bilateral teleoperation strategy, i.e., EMGP-VH, based on visual guidance, haptic constraint and mixed reality (MR) augmentation. To the best of our knowledge, electromagnetic field is first applied to serve the path planning of teleoperation in live-line maintenance. In visual guidance, EMG-potential fields are integrated into RRT* to calculate a low-energy path. At the same time, real-time haptic constraint is calculated based on a tube virtual fixture. MR augmentation also works as an indispensable part in both the platform construction and visual guidance. Our proposal has been extensively compared using seven objective performances and three subjective questionnaires both in simulation and real-world experiment with five different scenes and two approaches state-of-the-art, respectively. Functionality of EMGP-RRT* and effectiveness of haptic constraint are further analyzed. Results show that EMGP-RRT* has significant improvements both in searching efficiency and safety performances; and the proposed system (EMGP-VH) significantly contributes to improving telepresence and ensuring safe operations during live-line maintenance, resulting in a 30% reduction in operation time and a 60% decrease in trajectory offset.