System and method for purifying helium and application

The invention relates to the technical field of helium purification, and discloses a system and method for purifying helium and application. The system comprises a first gas-liquid separation device, a first-stage helium extraction tower (11), a second gas-liquid separation device, a second-stage helium extraction tower (27) and a denitrification tower (33) which are sequentially communicated, wherein the first gas-liquid separation device is used for carrying out first treatment on helium-containing natural gas (1) to convert the helium-containing natural gas into a first gas phase and a first liquid phase; the first-stage helium extraction tower (11) is used for carrying out first rectification on the first gas phase and the first liquid phase to obtain a second gas phase and a second liquid phase; the second gas-liquid separation device is used for performing second treatment on the second gas phase to convert the second gas phase into a third gas phase and a third liquid phase; the second-stage helium ext