Abstract: The subsurface sounding radar on Planet orbiter can detect the subsurface structure of the Planet surface with a high resolution, providing scientific data to the research on the Planet geologic structure. because of the far distence between the planet and the earth,huge qnantity of raw data cann't be transformed back to our own planet,so it's very important to process the radar return onboard the orbiter and only transform backto us far less quantity processing results.The detail analysis and engineering implement method of the Real-time backproject algorithm Processing technology for subsurface sounding radar on Planet orbiter is proposed.