Abstract: Exploration of Mars and other planets is a great mission in development of space remote sensing and deep space exploration. A brief review of the Mars exploration, e.g. available research results such as the distribution, structure and dielectric properties of Martian subsurface layers and the possibility of water existence etc., is presented. Microwave remote sensing technology shows great potential in future Mars exploration mission. Based on the advancement of both active and passive remote sensing in Earth science, some approaches to explore Martian regolith layers and possible detection of water existence in Martian subsurface layers are proposed. Scattering model of inhomogeneous media with rough interfaces for Mars exploration, imaging mechanism and numerical simulation are developed. The Mueller matrix solution of inhomogeneous media under pulse incidence are numerically simulated to illustrate funtional dependence on the planet characteristic parameters. Microwave radiometry and multi-data fusion technolonogy for Mars exploration are also presented. Some examples and technical key points are discussed.