Based on the data of ground, radiosonde, and numerical forecast data, an analysis is conducted on the foggy weather in the southern Shandong from 2001 to 2012, with the emphases on the climatic features, humidity, and physical quantity index in the nearground layer. It is found that: fogs in the southern Shandong were mainly concentrated in the period of October to December after 2010, and fog days increased significantly in the southern Shandong. The wet layer top of 90% relative humidity was lower than 925 hPa on average. The average height of the inversion layer during fogs in the southern Shandong was at 950 hPa, and there is an obvious weaktostrong warm advection center between 850 and 925 hPa, and the builtup time of the warm advection is 0 to 24 hours ahead of the fog. The formation of high humidity area at 925 hPa was 6 to 24 hours earlier than the apearing of the fog. The appearing of extreme descending motion values at 500 hPa was 6 to 24 hours earlier than the apearing of the fog, and the establishment of the obvious convergence center at 850-925 hPa was 0 to 24 hours earlier than the apearing of the fog.