With the increasing emphasis on near space in various countries, the importance of high-altitude drones with the ability to fly in near space is also increased. In order to obtain more accurate real-time information, it is necessary to significantly extend the flight time of high-altitude drones. Using laser wireless energy transmission technology to transmit energy to high-altitude drones is a feasible route to extend their flight time. Therefore, this paper conducted theoretical research on laser wireless energy transmission technology at long distance and analyzed the feasibility of using laser for wireless energy transmission to high-altitude drones in theory.The current problems such as insufficient transmission distance, low transmission power and low transmission efficiency on laser wireless energy transmission are found by investigating the current development status on laser wireless energy transmission technology at home and abroad. In order to enhance the transmission distance, transmission power and transmission efficiency of laser wireless energy transmission, the technical route for wireless energy transmission to high-altitude drones is proposed by comparing the laser source and photovoltaic cells, which using Yb doped fiber laser as the laser source, InGaAs photovoltaic cell as the photoelectric conversion module and combining laser relay technology. Based on the workflow of laser wireless energy transmission, the efficiencies of multiple workflows such as laser generation, transmission, reception and photoelectric conversion are analyzed, and then the system efficiency of using this technical route for laser wireless energy transmission to high-altitude drones is calculated. At the same time, the technical approaches to enhance the system efficiency of laser wireless energy transmission are discussed preliminary.According to the workflows of laser wireless energy transmission and based on the investigation of efficiencies in multiple workflows such as laser generation, transmission, reception and photoelectric conversion, the system efficiency of wireless energy transmission to high-altitude drones at the distance of 60 km can reach 11% to 14% by using the technical route proposed in this paper, which demonstrates the feasibility of laser wireless energy transmission to high-altitude drones at long distance theoretically. At present, the high power laser sources and InGaAs photovoltaic cells have basically met the requirements of wireless energy transmission at long distance, but the laser relay technology is still immature and requires in-depth research. The technical approaches to enhance the system efficiency of laser wireless energy transmission at long distance are discussed preliminarily. Besides the laser relay technology (Fig.3), the rational layout of photovoltaiccell arrays (Fig.6) and the phase modulation to laser beam by using phased array technology (Fig.7) also can enhance the systemefficiency of laser wireless energy transmission.The laser wireless energy transmission technology is a feasible solution to extend the flight time of the high-altitude drones. The investigation on the progresses of laser wireless energy transmission technology and the analysis on the current problems of laser wireless energy transmission technology are conducted in this paper. In order to solve the problems such as insufficient distance, low transmission power and low transmission efficiency of laser wireless energy transmission, a technical route is proposed to enhance the system efficiency of laser wireless energy transmission for the first time by using Yb doped fiber lasers as the laser source, InGaAs photovoltaic cells as the photoelectric conversion module and combining laser relay technology. The efficiencies of multiple workflows on wireless energy transmission are investigated and estimated, and then the system efficiency of ground laser wireless energy transmission to high-altitude drones at the distance of 60 km can reach 11% to 14% by calculation, which proves the feasibility of transmitting energy to high-altitude drones by laser theoretically. At present, the quantitative analysis and calculation about the system efficiency of laser wireless energy transmission at long distance aren't found in public literatures. At the same time, the technical approaches to enhance the system efficiency of laser wireless energy transmission at long distance are discussed preliminarily, such as reasonable layout of photovoltaic cell groups and using phased array technology to improve the uniformity of laser intensity distribution, which provides reference to the research on high power laser wireless energy transmission at long distance in future.