The invention relates to an overlapping type solution serial double-effect lithium bromide absorption refrigeration heat pump unit, and belongs to the technical field of air conditioner equipment. The overlapping type solution serial double-effect lithium bromide absorption refrigeration heat pump unit comprises a low-pressure generator (1), a high-pressure generator (2), a condenser (3), a high-temperature heat exchanger (4), an intermediate temperature heat exchanger (5), a low-temperature heat exchanger (6), a first absorber (7), a first evaporator (8), a second absorber (9) and a second evaporator (10). A lithium bromide solution flows through the high-pressure generator (2), the low-pressure generator (1), the first absorber (7) and the second absorber (9) in a series connection manner. A high-temperature heat source flows through the high-pressure generator (2). Low-temperature water flows through the first evaporator (8). Intermediate temperature water is divided into three paths, one path of intermediate temperature water flows through the second evaporator (10) and the first absorber (7) in a series connection manner, and the other two paths of intermediate temperature water flows through the second absorber (9) and the condenser (3) correspondingly. Through the unit, the refrigerating amount of the second evaporator in the overlapping type unit can be reduced, and accordingly the COP of the whole unit is improved.