Constant temperature method

The invention is applicable to the field of articles of daily use, and provides a constant temperature method. The method comprises the steps of 1, putting a cooled refrigerant or a heated heat retainer into a water bag; 2, wearing a constant temperature vest; 3, starting a miniature water pump and pumping liquid in the water bag into a pipeline; 4, making the liquid flow from the path of the pipeline into the water bag. When it is hot, the cooled refrigerant is put into the water bag to conduct thermal exchange with liquid in the water bag to cool the liquid in the water bag, through the miniature water pump, through a miniature water pump, low temperature liquid is pumped into the pipeline and is subjected to thermal exchange with the human body in the flowing process in the pipeline, the human body temperature is lowered, and the effect of cooling down is achieved; when it is cold, the heated heat retainer is put into the water bag to conduct thermal exchange with the liquid in thewater bag to heat the liq