The waste heat of circulating water in power plant recovered by absorption heat pump and used for urban central heating is a new energy saving technology, but the standards for its performance acceptance test have not been drafted. In the heat pump performance acceptance test, the uncertainty evaluation method of COP, the direct and indirect measuring parameters are analyzed, as well as the corresponding calculation formula is proposed. Then taking the waste heat utilization project of circulating water in a 300 MW heating unit as an example, the uncertainty assessment is carried out for the COP test of heat pump. The uncertainty calculation results show that the availability of the test results can be effectively improved by reducing the parameters’ measurement uncertainty, such as the water flow in heating network, the condensate flow, the water temperature at inlet and outlet of heat network, and so on.