The invention relates to a real-time extracting method of satellite remote sensing sea fog characteristic quantity, daytime EOS / MODIS data is used and is read into a raw data file PDS, the difference of sea fog and low cloud on a spectral characteristic is analyzed in two steps that: firstly, the sea fog and the low cloud are separated, and then, the sea fog characteristic quantity is extracted, namely that a three-level identifying method is adopted to orderly filter high cloud, middle cloud, low cloud, a cloudless water body, a solar flare water body, a cloud shadow area, a sea ice and a snow cover, the sea fog detection is established, a sea fog distributing area is obtained, a file which comprises a sea fog detecting result is generated, then, the sea fog characteristic quantity of the optical thickness of a fog area, the effective radius of fog and a liquid water path are calculated according to a formula, and pictures are displayed on a microcomputer. The method not only extracts the sea fog characteristic quantity, but also can calculate the visibility and the fog top height of the fog, consequently, the quantification detection of the sea fog is realized, and a dissipationforecast of the sea fog supplies meteorological information for air safety above the sea, maritime traffic and coastal airport operation.