Laser wireless power transmission in unmanned aerial vehicle, satellite station and lunar robot power supply has potential application prospect, whose efficiency becomes the key to the application bottleneck. In order to improve the electro-optic conversion efficiency of the transmitter, the spot uniformity and the effective power ratio in window at the receiver, a design scheme of high efficiency diode laser for the transmitter of laser wireless power transmission was proposed. A high power and high efficiency diode laser system was designed, which is based on space combination with high efficiency, what’s more, the unevenness of the intensity at the receiving end can be optimized to 0.207, and the power ratio in the effective window is more than 94%. A laser wireless power transmission experimental device was built, whose power is over kilowatt, and the rectangular spot was outputted directly by diode laser system, which is matched with rectangular photovoltaic cell, thus the battery array layout rate was improved. The feature of multi-beam modulation was used to improve uniformity of the intensity, which is beneficial to improve the optic–electro conversion efficiency of battery and simplify the power management at the receiving end. The design and research provide reference for the practical application of laser wireless power transmission.