Ultra-low temperature circulation refrigeration method employing injectors

The invention relates to an ultra-low temperature circulation refrigeration method employing injectors. In the method, high-pressure mixed refrigerants compressed by a compressor (1) enter a condenser (2) and then enter a first gas-liquid separator (3) to realize gas and liquid phase separation, liquid refrigerants flowing out of the first gas-liquid separator (3) enter a first injector (4), gas and liquid two-phase mixed work media from an outlet of the first injector (4) are cooled by a first heat regenerator (5) and then enter a second gas-liquid separator (6) to be separated, work fluid of a second injector (8) is processed into low-pressure steam through a first throttling member (7) and a condensing evaporator (9), and the low-pressure steam is pressurized by the second injector (8), flows into the first heat regenerator (5) to be subjected to overheating and then flows back to the compressor (1); and gaseous refrigerants flowing out of the top of the first gas-liquid separator (3) flow into the condensing evaporator (9), are recooled through a second heat regenerator (10) and enter an evaporator (12) through a second throttling member (11) for refrigeration at low temperature, the ultra-low temperature can reach minus 40 DEG C to minus 170 DEG C, and the energy saving effect is good.