Based on the hourly observation data from 122 national meteorological stations in Shandong, the spatio-temporal distribution of 61 regional radiation fog processes in Shandong from 2016 to 2019 and characteristics of key meteorological elements are analyzed. The results are shown below. 1) There is an evident seasonal variation for radiation fog, which occurs most frequently from October to next February, and long-lasting heavy fog occurs most frequently in January and December. Its diurnal variation is also significant, the fog frequency increases from 20:00 to 07:00 next day with the high frequency during the period from 02:00 to 08:00 and the peak at around 07:00, while there is usually no thick radiation fog in the afternoon. 2) The radiation fog occurs more frequently in the west than in the east of Shandong. In detail, more fog events occur over the northwest and southwest of Shandong and less in the mountainous areas and coastal regions. The thick fog and dense fog events with the visibility lower than 200 m are mainly distributed in Dezhou, Liaochen, and Heze. 3) When the regional radiation fog occurs, the meteorological elements have the following characteristics. There are no significantly preferred wind directions although the northerly overwhelms the others to some degree, and the wind speed is mostly less than 3 m·s-1. The air temperature and dew point both decreases before the formation of all levels of fogs, and radiation fog tends to occur when the difference between the air temperature at 20:00 and the minimum air temperature of the following day lies between 2 ℃ and 6 ℃ and the difference between the dew point at 14:00 and that of the instant the minimum visibility occurs lies between 1 ℃ and 5 ℃. The heavier the fog, the higher the requirements for lower depression of the dew point and higher relative humidity. Most of the fog events with the visibility lower than 1 000 m are accompanied with the depression of the dew point lower than 2 ℃ and relative humidity higher than 90%. When the fog events with the visibility lower than 500 m occur, the depression of the dew point decreases to be lower than 1 ℃ and the relative humidity increases to be more than 95%.