With the development of smart power grid， Unmanned Aerial Vehicles （UAVs） are more and more widely used for inspection of transmission lines. In order to effectively implement fault location and type judgment of transmission lines， UAVs are required to transmit videos and images with high resolution. Under the condition of limited bandwidth， it is necessary to improve the spectral efficiency of UAV return communication link as much as possible to meet the transmission rate requirements of high-resolution videos and images. A video image transmission communication method based on mesh network was proposed. By deploying the wireless access nodes on tower and building Mesh network， the communication devices carried by UAVs could communicate with the built Mesh network as the network nodes at any time. After capturing a video of the failure on transmission lines， the video could be quickly transmitted to the data center by UAVs. For this purpose， the communication module of the patrol UAV was equipped with a large-scale antenna array， in millimeter wave frequency band， a heuristic point-to-point directional hybrid beamforming method was adopted to improve the spectral efficiency of receiving communication link. The simulation results show that the performance of the proposed method is better than that of the Orthogonal Matching Pursuit （OMP） method and is closer to that of the fully digital beamforming method.