Jet enthalpy technology can improve the low-temperature performance degradation of air source heat pumps, but it is still necessary to integrate auxiliary heat sources to supplement the heating gap in extremely cold regions. Solar energy is widely used as one of the most commonly used auxiliary heat sources. However, the traditional integrated system of solar energy and air source heat pumps is difficult to achieve efficient operation under wide-range working conditions. Therefore, this paper proposes a new solar-assisted enhanced jet enthalpy air source heat pump. Solar energy is used to heat the refrigerant in the jet branch to increase the flow rate of the jet branch, which enhances the effect of jet enthalpy. The operational performance of the new system is studied and analyzed by combining experimental and simulation methods. The results show that the new system is highly efficient in the utilization of medium-grade solar energy and has a significant effect on improving quality and increasing quantity. Its heating capacity and coefficient of performance are both superior to the existing integrated systems. The research in this paper provides a new idea for promoting the popularization of air source heat pump heating technology in extremely cold regions.