To improve the efficiency of Air Source Heat Pump（ASHP）system and that of Triple-sleeve Energy Exchanger (TRESE) for space heating during low ambient temperature conditions，the space heating by TRESE with solar thermal energy assisted was built and implemented. The experimental results suggest that heating efficiency can be enhanced through increasing temperature or flow rate of solar hot water. Furthermore，in the same flow rate and temperature of the supply / return water for space heating，the power consumption would reduce by 42% and 41% respectively，while the capacity of space heating by TRESE with solar thermal energy assisted would ascend by 57% and 13% respectively, compared with that of space heating by ASHP or TRESR without solar thermal energy assisted. Consequently，space heating by TRESE with solar thermal energy assisted can achieve encouraging energy efficiency with smoothly running under low temperature outside.