In response to the escalation of global warming, low efficiency of traditional heating methods, and high pollution levels, this study investigated a novel wide-temperature-zone heat-pump air-conditioning system for buildings, which employs an eco-friendly non-eutectic working fluid. It integrates the single-stage vapor compression cycle and the auto-cascade heat-pump cycle, enabling efficient heating and cooling from -20 ℃ to 40 ℃ ambient temperature. The viability of the system was tested in Shenyang and compared with that of a conventional R134a air-conditioning system for cooling and a coal-fired boiler for heating. The thermodynamic evaluation indicated coefficient of performance of 3-5.47 in the cooling mode and 1.81 in the heating mode at -20 ℃. Experimental validation confirmed stable operation across a range of -20 ℃ to 40 ℃, with a heating coefficient of performance of 1.4 at -20 ℃. This research provides theoretical support for the advancement of green building development using wide-temperature-zone heat-pump technology.