Abstract: Like the Earth, Mars is surrounded by an ionosphere of different densities. This can be explored using radio occultation technology, but there are limitations in the precision and range of exploration. In October 2009, the Phobos-Grunt and Yinghuo-1 satellites will be launched as part of the joint Russian and Chinese Martian exploration project, and the first international satellite-to-satellite radio occultation experiment on the Martian ionosphere will be implemented. This will focus on the midday and midnight ionosphere which cannot be sounded by satellite-to-Earth radio occultation. Dual bands will be selected in the satellite-to-satellite experiment. The sensitivity of the radio occultation receiver is -145dBm, and the phase measurement error less than 5% of a cycle. The receiverhas been tested with dynamic simulation on the ground, and from the data acquired it is found that the Martian ionosphere density profiles are inversed quite well.