Using investigation on water temperature in Jiaozhou Bay in May, August and November 1979, this paper analyzed horizontal distributions, and defined the high water temperature regions. Results showed that water temperature in May, August, and October 1979 were 11.60-16.50 °C, 24.02-28.70 °C, and 16.21-18.39 °C, respectively. In May, the variation range of water temperature in the coastal waters in the north of the bay was 1.20 °C, while in the inner side, middle and outer side of the bay mouth was 0.10 °C. In August, the variation range of water temperature in the inner side and middle of the bay mouth was 1.42 °C. In October, the variation range of water temperature in the inner side and middle of the bay mouth was 0.14 °C, compared with 0.53 °C in the coastal waters in the north of the bay. In May, August, and October, there were high water temperature regions from the coast waters in the northeast of the bay to the north of the bay, from the coastal waters in the east of the bay to the north of the bay, and in the outer side of the bay mouth, in where the water temperature ranged from 15.30-16.50 °C, 28.09-28.70 °C, and 18.39 °C, respectively.