The present invention relates to a method that obtains emissivity or reflectivity based on ratios of the brightness temperature measured by a satellite and the land surface temperature, calculates two reflectivity using polarizing features of a microwave according to surface characteristics, and measures a volumetric soil water content of a land surface considering that water has different physical characteristics from those of soil. In particular, it may be possible to measure volumetric soil water contents on territories of other countries as well as regions which have many limitations and troubles in direct measurement of the volumetric soil water contents. Accordingly, valuable materials in terms of nation economy may be produced together with substantial contribution to industrial fields that have direct effects on agriculture and disaster prevention.