Abstract: In order to reduce the negative effects of frost formation on the LNG ambient air vaporizer（AAV）performance during operation,an LNG vaporization system utilizing solar assisted heat pump（DX-SAHPNV）was proposed and designed,and the dynamic numerical model for the DX-SAHPNV system was developed in this paper. According to the simulation results,the improvement on the AAV thermal performance was analyzed in detail,as well as the dynamic operation performance of DX-SAHPNV throughout the year.The system performance whether transferring LNG into the collector/evaporator or not was also compared. The results show that compared with the traditional AAV,the DX-SAHPNV system can greatly shorten the length of the liquid zone and two-phrase zone in the AAV pipe both on the typical winter and summer days. This can reduce the amount of frost on the AAV surface and increase the average temperature of natural gas at the outlet of AAV by 3.31 K and 7.46 K on the typical winter and summer days,respectively. If LNG is introduced into the collector/evaporator,the COP of the DX-SAHPNV system will be 9.25% and 16.49% higher than that without introducing LNG into it,and the heat collection efficiency will be increased by 11.07% and 14.95% on the typical winter and summer days,respectively. Similarly,the annual average COP of the DX-SAHPNV system and the annual collector efficiency of the collector/evaporator is increased by 13.64% and 12.84%,respectively. The DX-SAHPNV system can significantly improve the vaporization efficiency of AAV.