With the soil source heat pump system of Nanhua University as an example, investigated the operating characteristics of cooling conditions in summer. Measured the initial soil temperature distribution before heat pump operating, and tested respectively the soil temperature changed, the inlet and outlet water temperature in the underground exchanger and the heat transfer capacity under continuous and intermittent cooling operation. The results indicated that under the intermittent operation at the soil initial temperature of 19.77 ℃, the soil temperature was increased by 2.3 ℃, inlet and outlet water temperature were increased by 2 ℃ and 2.3 ℃, and the unit well depth change heat increased by 25% , respectively, when compared with continuous operation.