The invention relates to a method to improve the antifreeze ability for air condition. It includes the following steps: minimum water flow would be controlled by a flow controller at water outlet, setting an antifreeze value, when water temperature lowering than the value, the set would stop running and output alarm. If the water temperature at water intake is lower than a set temperature value, and the temperature difference at outlet and intake exceeding a set value, and lasting for a time span, it would be judged as not enough water flow. The machine would be stopped and output alarm.