Abstract: In order to improve the efficiency of the transcritical CO₂ water-water heat pump system, a system simulation model was established according to the existing experimental bench, and experimental tests and numerical simulations were carried out respectively, and the accuracy of the simulation model was verified by experimental data. Based on the purpose of producing hot water, the influence of operating parameters on system performance is simulated and analyzed, and the results show that increasing the superheat can increase Coefficient of Performance（COP）, and the water supply temperature at the user side increases by an average of 11.3℃； with the increase of high pressure, the water supply temperature at the user side increases, and the COP is maximized by an optimal high pressure; increasing the flow rate and inlet temperature of chilled water, the heating efficiency of the system can be increased by about 40%, but the water supply temperature at the user side does not change much. According to the experimental and simulation results, a solar-assisted transcritical CO₂ heat pump dual evaporator system is designed, which can realize three different operation modes, which can improve the chilled water inlet temperature and increase the system efficiency. Compared with electric heating boilers and gas boilers, the total investment of solar heat pumps is same as the total investment of the above two heating methods in the 5th and 7th years, respectively. Its total investment in 20 years of operation is 39% and 49% less than gas boilers and electric heating boilers, respectively, which has obvious economic advantages and practical promotion value.