The invention relates to a real-time acquiring method for sea fog thickness and cloud base height of low clouds. The method fully utilizes data from L wave band secondary wind-detecting radar and digital dropsonde data of an observatory, orderly analyzes distribution characteristics of the temperature and moisture of sea fog and the low clouds in the vertical direction, calculates stability degree conditions and turbulent flow conditions of lower atmosphere when the sea fog and the low clouds exist, makes statistical analysis and concludes the conditions to separate the sea fog and the low clouds, calculates the sea fog thickness and the low clouds height, and acquires the sea fog thickness and the low clouds height. The formed computer software automatically displays the result. The invention provides an effective method for monitoring in real time, namely simultaneously establishing an objective and feasible method for automatically extracting the cloud base height of the low clouds and monitoring the sea fog thickness in real time, has strong implementation, high reliability, and provides effective meteorological data for flight safety above the sea surface, maritime traffic transportation, as well as operations on harbors and costal airports.