The invention discloses a judging method and device of an air conditioning heat pump system during refrigerant charging. The method comprises the following steps that in the process of refrigerant charging, the upstream temperature and the downstream temperature of a charging valve are detected in real time; the temperature difference value between the upstream temperature and the downstream temperature is obtained; whether the temperature difference value is less than or equal to a preset threshold value or not is judged; and if the temperature difference value is less than or equal to the preset threshold value, the fact that refrigerant loss of a refrigerant tank exists is judged, and the charging valve is controlled to be closed. In this way, whether a refrigerant further exists in therefrigerant tank or not can be judged intelligently, so that in the absence of the refrigerant, the refrigerant tank can be replaced timely.