A constant temperature system for a culture pond, comprising a temperature rising unit, a cooling unit, and an adjusting unit. The heating unit comprises a water supply source, a water supply line, a boiler connected to the water supply line, and a high temperature line connecting the boiler. The cooling unit comprises a water supply source, a water inlet pipeline, a cold water tower connected to the water inlet pipeline, and a water outlet pipeline connecting the cold water tower. The adjusting unit comprises a steam regulating valve connected to the high temperature pipeline, a cold water regulating valve connected to the water outlet pipeline, and an output pipeline connecting the steam regulating valve and the cold water regulating valve. The steam regulating valve and the cold water regulating valve can mix the high temperature steam and the cold water into the warm water of an appropriate temperature according to the water temperature of the breeding pool, and finally send the warm water into the breeding pool to maintain the water temperature of the water.一種養殖池之恆溫系統，包含一升溫單元、一降溫單元，及一調節單元。該升溫單元包括一供水源、一供水管路、一連接該供水管路的鍋爐，及一連接該鍋爐的高溫管路。該降溫單元包括一輸水源、一進水管路、一連接該進水管路的冷水塔，及一連接該冷水塔的出水管路。該調節單元包括一連接該高溫管路的蒸汽調節閥、一連接該出水管路的冷水調節閥，及一連接該蒸汽調節閥及該冷水調節閥的輸出管路。該蒸汽調節閥及該冷水調節閥可視該養殖池的水溫將高溫蒸汽及冷水混合成適當溫度的溫水，最後將溫水送入養殖池內以維持池水溫度。
