On the basis of the ratio of electricity consumption to transferred heat quantity (EHR), combined with primary energy consumption rate and propagated in the national building energy efficiency design standard, the index of primary energy consumption ratio of heating supplied (PEHR) is established. According to the requirements of PEHR control index of the absorption heat pump district heating system, the maximum heating range is obtained. The lower limit heating coefficient of the heat pump unit expression is deduced when the absorption heat pump district heating system is more energy-saving than traditional boiler heating system. The results show that when the coefficient of the absorption heat pump is certain, the greater the PEHR control value, the more extensive the reasonable heating range; the larger the area value, the smaller the reasonable heating range. The lower limit of heating coefficient of the absorption heat pump not only increases with the improvement of the thermal efficiency of the boiler, but increases with the increase in the scope of the district heating range. Therefore the smallscale absorption heat pump district heating system is benefit for energy-saving