Speeding up the development of utilizing renewable energy is a significant move for realizing sustainable development in China. Using seawater as an energy resource for heat pumps to provide district cooling and heating offers several advantages. This study is an evaluation of the potential natural conditions for using seawater heat pump to provide heating and cooling for areas in Dalian. The amount of thermal energy produced is dependent upon the water temperature. Therefore, it is important to find out the temperature distribution both in space and time. Through the analysis of the distribution features of the Yellow Sea and Bo Sea temperature in winter and summer, it is shown that distributions in many places are favourable to using a heat pump to produce thermal energy. The investigation is focused on the following: long and short term temperature distributions along the Dalian's coast; salinity and temperature vertical stratification; and optimization of the intake depths.