Based on the observation data of daily maximum and minimum temperature between June and August from 1961 to 2019 from 88 meteorological stations in Shandong, the spatio-temporal variation and mutation characteristics of the extreme hot daytime, extreme hot nighttime, extreme hot days are analyzed using three extreme temperature indices. The results are shown below. 1) The number of extreme hot events that happened in the nighttime and happened both in the daytime and nighttime increases with stronger intensity and higher frequency. The annual frequency, proportion, and mean intensity of extreme hot daytime have decreasing tendency, and the decreasing tendency of proportion is the most significant; the annual frequency, proportion, and mean intensity of extreme hot nighttime and extreme hot days have increasing tendency. 2) The variations of extreme hot events in inland and coastal regions of Shandong are obviously different. The indices of extreme hot daytime have significantly decreasing tendency in inland areas and the variation tendency in most areas passes the significance test at 0.05 level, while the indices have increasing tendency in some areas of the south and east of Shandong Peninsula; the indices of extreme hot nighttime have significantly increasing tendency in the middle and west of Shandong and the variation tendency in most areas passes the significance test at 0.05 level; the indices of extreme hot days have significantly increasing tendency in the middle and east of Shandong, especially in Shandong Peninsula, and the variation tendency in most areas passes the significance test at 0.05 level. 3) The mutations of the extreme hot events’ indices are varied. For extreme hot daytime, the frequency does not mutate, the mean intensity mutates around 1970, and the mean intensity have obviously decreased since the mutation; for extreme hot nighttime, the frequency and mean intensity both mutate around 1994, and the frequency and mean intensity have obviously increased since the mutation; for extreme hot days, the frequency and intensity mutate around 1994 and 1973, respectively, and the frequency has obviously increased since the mutation.