In this paper a novel system of the X band radiometer scatterometer developed by our Institutions is reported. By using this system, multi polarized (VV,HH,VH,HV) backscattering coefficients for active remote sensing and V,H polari zed brightness temperature for passive remote sensing can be measured simultan eously. Some measurements of scattering and emission from tree canopy with and without artificial metal targets are presented. Theoretical study of scattering and emission from a layer of random medium is discussed with data analysis. Ou r approach provides an example of correlated active passive remote sensing and application for target detection in environmental clutters.