Abstract: It established a experimental device about direct expansion more solar collector evaporator parallel with heat pump system,in the extreme working condition,the thermal performance of solar heat pump is analyzed.It shows that under the extreme working condition,though there are differences of two evaporator sets heat absorption and even a evaporator consume too little heat causes coolant overheat is close to zero,but the COP of the system reaches 3.69.Therefore,the thermal property of evaporators in parallel can meet request.The more heat absorption,the higher refrigerant superheat at the exit.It proves that direct-expansion solar heat pump system of evaporators in parallel is reliable.