In order to achieve reliable and steady transmission of HD images, substation autonomous patrol robot uses a combination of WLAN and 3G/GPRS. The robot uses reliable and steady 3G/GPRS network to transmit necessary image data, and uses WLAN network to transmit unnecessary real-time HD videos. This paper designs an image server and a control client, implements each subroutine for different cameras by using a dedicated SDK and the open source project Live555+FFmpeg. The image server can transmit image data and forward real-time video stream correctly. The control client can receive and save image data and play real-time video, the images is clear and the transmission delay is small.